UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549


                                  SCHEDULE 13G

                                 (RULE 13D-102)

                 INFORMATION TO BE INCLUDED IN STATEMENTS FILED
          PURSUANT TO RULE 13D-1(B)(C), AND (D) AND AMENDMENTS THERETO
                         FILED PURSUANT TO RULE 13D-2(B)

                                (Amendment No. 1)
                                 Callwave, Inc.
--------------------------------------------------------------------------------
                                (Name of Issuer)
                         Common Stock, $.0001 par value
--------------------------------------------------------------------------------
                         (Title of Class of Securities)
                                   13126N 10 1
                ------------------------------------------------
                                 (CUSIP Number)
                                December 31, 2005
--------------------------------------------------------------------------------
             (Date of Event Which Requires Filing of this Statement)

Check the  appropriate box to designate the rule pursuant to which this Schedule
is filed:

[ ]    Rule 13d-1(b)

[ ]    Rule 13d-1(c)

[X]    Rule 13d-1(d)

       * The  remainder  of this cover page shall be filled out for a  reporting
person's  initial  filing on this  form with  respect  to the  subject  class of
securities,  and for any subsequent amendment containing information which would
alter the disclosures provided in a prior cover page.

       The information required in the remainder of this cover page shall not be
deemed to be "filed"  for the purpose of Section 18 of the  Securities  Exchange
Act of 1934 ("Act") or otherwise  subject to the  liabilities of that section of
the Act but shall be subject to all other  provisions of the Act  (however,  see
the Notes).

                               Page 1 of 14 pages



                                  SCHEDULE 13G
ISSUER:  Callwave, Inc.                                  CUSIP No.:  13126N 10 1
--------------------------------------------------------------------------------

   1.   Names of Reporting Persons.
        I.R.S. Identification Nos. of above persons (entities only).

        Insight Venture Partners IV, L.P.

        52-2269503
        ........................................................................
--------------------------------------------------------------------------------

   2.   Check the Appropriate Box if a Member of a Group (See Instructions)

        (a) ....................................................................

        (b) ....................................................................
--------------------------------------------------------------------------------

   3.   SEC Use Only ...........................................................
--------------------------------------------------------------------------------

   4.   Citizenship or Place of
        Organization              Delaware
                                  ..............................................
--------------------------------------------------------------------------------
                          Sole Voting
                     5.   Power             2,395,490
                                            ....................................
                   -------------------------------------------------------------
                          Shared Voting
 Number of Shares    6.   Power
 Beneficially                               ....................................
 Owned by Each     -------------------------------------------------------------
 Reporting Person         Sole Dispositive
 With:               7.   Power             2,395,490
                                            ....................................
                   -------------------------------------------------------------
                          Shared Dispositive
                     8.   Power
                                            ....................................
--------------------------------------------------------------------------------

 9.     Aggregate Amount Beneficially Owned by Each
        Reporting Person                                 2,395,490
                                                         .......................

 10.    Check box if the Aggregate Amount in Row (9)
        Excludes Certain Shares (See Instructions)
                                                         .......................

 11.    Percent of Class Represented by
        Amount in Row (9)                 11.6%
                                          ......................................
--------------------------------------------------------------------------------
 12. Type of Reporting Person (See Instructions)
--------------------------------------------------------------------------------
PN
.................................................................................

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                               Page 2 of 14 pages



                                  SCHEDULE 13G
ISSUER:  Callwave, Inc.                                  CUSIP No.:  13126N 10 1
--------------------------------------------------------------------------------

   1.   Names of Reporting Persons.
        I.R.S. Identification Nos. of above persons (entities only).

        Insight Venture Partners IV (Co-Investors), L.P.

        52-2269509
        ........................................................................
--------------------------------------------------------------------------------

   2.   Check the Appropriate Box if a Member of a Group (See Instructions)

        (a) ....................................................................

        (b) ....................................................................
--------------------------------------------------------------------------------
        SEC Use
   3.   Only
                ................................................................
--------------------------------------------------------------------------------
        Citizenship or Place of
   4.   Organization              Delaware
                                  ..............................................
--------------------------------------------------------------------------------
                          Sole Voting
                     5.   Power         295,217
                                        ........................................
                   -------------------------------------------------------------
                          Shared Voting
 Number of Shares    6.   Power
 Beneficially                           ........................................
 Owned by Each     -------------------------------------------------------------
 Reporting Person         Sole Dispositive
 With:               7.   Power         295,217
                                        ........................................
                   -------------------------------------------------------------
                          Shared Dispositive
                     8.   Power
                                        ........................................
--------------------------------------------------------------------------------

 9.     Aggregate Amount Beneficially Owned by Each
        Reporting Person                                 295,217
                                                         .......................

 10.    Check box if the Aggregate Amount in Row (9)
        Excludes Certain Shares (See Instructions)
                                                         .......................

 11.    Percent of Class Represented by
        Amount in Row (9)                 1.4%
                                          ......................................
--------------------------------------------------------------------------------
 12. Type of Reporting Person (See Instructions)
--------------------------------------------------------------------------------
PN
.................................................................................

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.................................................................................

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                               Page 3 of 14 pages



                                  SCHEDULE 13G
ISSUER:  Callwave, Inc.                                  CUSIP No.:  13126N 10 1
--------------------------------------------------------------------------------

   1.   Names of Reporting Persons.
        I.R.S. Identification Nos. of above persons (entities only).

        Insight Venture Partners IV (Fund B), L.P.

        52-2269507
        ........................................................................
--------------------------------------------------------------------------------

   2.   Check the Appropriate Box if a Member of a Group (See Instructions)

        (a) ...................................................................

        (b) ...................................................................
--------------------------------------------------------------------------------
        SEC Use
   3.   Only
                ...............................................................
--------------------------------------------------------------------------------
        Citizenship or Place of
   4.   Organization              Delaware
                                  ..............................................
--------------------------------------------------------------------------------
                          Sole Voting
                     5.   Power         19,033
                                        ........................................
                   -------------------------------------------------------------
                          Shared Voting
 Number of Shares    6.   Power
 Beneficially                           ........................................
 Owned by Each     -------------------------------------------------------------
 Reporting Person         Sole Dispositive
 With:               7.   Power         19,033
                                        ........................................
                   -------------------------------------------------------------
                          Shared Dispositive
                     8.   Power
                                        ........................................
--------------------------------------------------------------------------------

 9.     Aggregate Amount Beneficially Owned by Each
        Reporting Person                                 19,033
                                                         .......................

 10.    Check box if the Aggregate Amount in Row (9)
        Excludes Certain Shares (See Instructions)
                                                         .......................

 11.    Percent of Class Represented by
        Amount in Row (9)                 0.1%
                                          ......................................
--------------------------------------------------------------------------------
 12. Type of Reporting Person (See Instructions)
--------------------------------------------------------------------------------
PN
.................................................................................

.................................................................................

.................................................................................

.................................................................................

.................................................................................

.................................................................................

--------------------------------------------------------------------------------

                               Page 4 of 14 pages



                                  SCHEDULE 13G
ISSUER:  Callwave, Inc.                                  CUSIP No.:  13126N 10 1
--------------------------------------------------------------------------------

   1.   Names of Reporting Persons.
        I.R.S. Identification Nos. of above persons (entities only).
        Insight Venture Partners (Cayman) IV, L.P.

        90-0183706
        ........................................................................
--------------------------------------------------------------------------------

   2.   Check the Appropriate Box if a Member of a Group (See Instructions)

        (a) ...................................................................

        (b) ...................................................................
--------------------------------------------------------------------------------
        SEC Use
   3.   Only
                ...............................................................
--------------------------------------------------------------------------------
        Citizenship or Place of
   4.   Organization              Cayman Islands
                                  ..............................................
--------------------------------------------------------------------------------
                          Sole Voting
                     5.   Power         320,256
                                        ........................................
                   -------------------------------------------------------------
                          Shared Voting
 Number of Shares    6.   Power
 Beneficially                           ........................................
 Owned by Each     -------------------------------------------------------------
 Reporting Person         Sole Dispositive
 With:               7.   Power         320,256
                                        ........................................
                   -------------------------------------------------------------
                          Shared Dispositive
                     8.   Power
                                        ........................................
--------------------------------------------------------------------------------

 9.     Aggregate Amount Beneficially Owned by Each
        Reporting Person                                 320,256
                                                         .......................

 10.    Check box if the Aggregate Amount in Row (9)
        Excludes Certain Shares (See Instructions)
                                                         .......................

 11.    Percent of Class Represented by
        Amount in Row (9)                 1.6%
                                          ......................................
--------------------------------------------------------------------------------
 12. Type of Reporting Person (See Instructions)
--------------------------------------------------------------------------------
PN
.................................................................................

.................................................................................

.................................................................................

.................................................................................

.................................................................................

.................................................................................

--------------------------------------------------------------------------------

                               Page 5 of 14 pages



                                  SCHEDULE 13G
ISSUER:  Callwave, Inc.                                  CUSIP No.:  13126N 10 1
--------------------------------------------------------------------------------

   1.   Names of Reporting Persons.
        I.R.S. Identification Nos. of above persons (entities only).

        Insight Venture Associates IV, LLC

        37-1417641
        ........................................................................
--------------------------------------------------------------------------------

   2.   Check the Appropriate Box if a Member of a Group (See Instructions)

        (a) ...................................................................

        (b) ...................................................................
--------------------------------------------------------------------------------
        SEC Use
   3.   Only
                ...............................................................
--------------------------------------------------------------------------------
        Citizenship or Place of
   4.   Organization              Delaware
                                  ..............................................
--------------------------------------------------------------------------------
                          Sole Voting
                     5.   Power
                                        ........................................
                   -------------------------------------------------------------
                          Shared Voting
 Number of Shares    6.   Power         3,029,996
 Beneficially                           ........................................
 Owned by Each     -------------------------------------------------------------
 Reporting Person         Sole Dispositive
 With:               7.   Power
                                        ........................................
                   -------------------------------------------------------------
                          Shared Dispositive
                     8.   Power         3,029,996
                                        ........................................
--------------------------------------------------------------------------------

 9.     Aggregate Amount Beneficially Owned by Each
        Reporting Person                                 3,029,996
                                                         .......................

 10.    Check box if the Aggregate Amount in Row (9)
        Excludes Certain Shares (See Instructions)
                                                         .......................

 11.    Percent of Class Represented by
        Amount in Row (9)                 14.7%
                                          ......................................
--------------------------------------------------------------------------------
 12. Type of Reporting Person (See Instructions)
--------------------------------------------------------------------------------
OO
.................................................................................

.................................................................................

.................................................................................

.................................................................................

.................................................................................

.................................................................................

--------------------------------------------------------------------------------

                               Page 6 of 14 pages



                                  SCHEDULE 13G
ISSUER:  Callwave, Inc.                                  CUSIP No.:  13126N 10 1
--------------------------------------------------------------------------------

   1.   Names of Reporting Persons.
        I.R.S. Identification Nos. of above persons (entities only).

        Insight Holdings Group, LLC

        35-2158588
        ........................................................................
--------------------------------------------------------------------------------

   2.   Check the Appropriate Box if a Member of a Group (See Instructions)

        (a) ...................................................................

        (b) ...................................................................
--------------------------------------------------------------------------------
        SEC Use
   3.   Only
                ...............................................................
--------------------------------------------------------------------------------
        Citizenship or Place of
   4.   Organization              Delaware
                                  ..............................................
--------------------------------------------------------------------------------
                          Sole Voting
                     5.   Power
                                        ........................................
                   -------------------------------------------------------------
                          Shared Voting
 Number of Shares    6.   Power         3,029,996
 Beneficially                           ........................................
 Owned by Each     -------------------------------------------------------------
 Reporting Person         Sole Dispositive
 With:               7.   Power
                                        ........................................
                   -------------------------------------------------------------
                          Shared Dispositive
                     8.   Power         3,029,996
                                        ........................................
--------------------------------------------------------------------------------

 9.     Aggregate Amount Beneficially Owned by Each
        Reporting Person                                 3,029,996
                                                         .......................

 10.    Check box if the Aggregate Amount in Row (9)
        Excludes Certain Shares (See Instructions)
                                                         .......................

 11.    Percent of Class Represented by
        Amount in Row (9)                 14.7%
                                          ......................................
--------------------------------------------------------------------------------
 12. Type of Reporting Person (See Instructions)
--------------------------------------------------------------------------------
OO
.................................................................................

.................................................................................

.................................................................................

.................................................................................

.................................................................................

.................................................................................

--------------------------------------------------------------------------------


                               Page 7 of 14 pages



                                  SCHEDULE 13G
ISSUER:  Callwave, Inc.                                  CUSIP No.:  13126N 10 1


ITEM 1.

                  (A)      NAME OF ISSUER:

                           Callwave, Inc.

                  (B)      ADDRESS OF ISSUER'S PRINCIPAL EXECUTIVE OFFICES:

                           136 West Canon Perdido Street
                           Santa Barbara, CA 93101

ITEM 2.

                           NAME OF PERSON FILING:

                           Insight Venture Partners IV, L.P. ("IVP")

                           Insight Venture Partners IV (Co-Investors), L.P.
                             ("IVP Co-Investors")
                           Insight  Venture  Partners  (Fund B), L.P. ("IVP Fund
                             B")
                           Insight  Venture  Partners  (Cayman)  IV, L.P.  ("IVP
                             Cayman")
                           Insight Venture Associates IV, LLC ("Associates")
                           Insight Holdings Group, LLC ("Holdings")

                           Supplemental  information  relating to the  ownership
                           and control of the person  filing this  statement  is
                           included in Exhibit 2(a) attached hereto.

                  (A)      ADDRESS  OF  PRINCIPAL  BUSINESS  OFFICE OR, IF NONE,
                           RESIDENCE:

                           c/o Insight Capital Partners
                           680 Fifth Avenue, 9th Floor
                           New York, NY 10019

                  (B)      CITIZENSHIP:

                           For all  reporting  persons  (other than IVP Cayman):
                           Delaware
                           IVP Cayman: Cayman Islands

                  (C)      TITLE OF CLASS OF SECURITIES (OF ISSUER):

                           Common Stock, $.0001 par value

                  (D)      CUSIP NUMBER:

                           13126N 10 1

ITEM 3.  IF THIS  STATEMENT IS FILED  PURSUANT TO SS.SS.  240.  13D-1(B) OR 240.
         13D-2(B) OR (C), CHECK WHETHER THE PERSON FILING IS A:

                  Not Applicable

ITEM 4.  OWNERSHIP

                  (A)      AMOUNT BENEFICIALLY OWNED:

                           IVP              :     2,395,490
                           IVP Co-Investors :       295,217
                           IVP Fund B       :        19,033
                           IVP Cayman       :       320,256
                           Associates       :     3,029,996
                           Holdings         :     3,209,996

                               Page 8 of 14 pages



                                  SCHEDULE 13G
ISSUER:  Callwave, Inc.                                  CUSIP No.:  13126N 10 1


                  (B)      PERCENT OF CLASS:

                           IVP              :     11.6%
                           IVP Co-Investors :      1.4%
                           IVP Fund B       :      0.1%
                           IVP Cayman       :      1.6%
                           Associates       :     14.7%
                           Holdings         :     14.7%

                  (C)      NUMBER OF SHARES AS TO WHICH SUCH PERSON HAS:

                           (i)      Sole  power to  vote:  IVP:  2,395,490,  IVP
                                    Co-Investors:  295,217,  IVP Fund B: 19,033,
                                    IVP   Cayman:   320,256,    Associates:   0,
                                    Holdings: 0

                           (ii)     Shared   power   to   vote:   IVP:   0,  IVP
                                    Co-Investors:  0, IVP Fund B: 0, IVP Cayman:
                                    0,    Associates:    3,029,996,    Holdings:
                                    3,029,996

                           (iii)    Sole power to dispose:  IVP: 2,395,490,  IVP
                                    Co-Investors:  295,217,  IVP Fund B: 19,033,
                                    IVP   Cayman:   320,256,    Associates:   0,
                                    Holdings: 0

                           (iv)     Shared   power  to  dispose:   IVP:  0,  IVP
                                    Co-Investors:  0, IVP Fund B: 0, IVP Cayman:
                                    0,    Associates:    3,029,996,    Holdings:
                                    3,029,996

ITEM 5.  OWNERSHIP OF FIVE PERCENT OR LESS OF A CLASS

                  Not applicable

ITEM 6.  OWNERSHIP OF MORE THAN FIVE PERCENT ON BEHALF OF ANOTHER PERSON

                  Not applicable.

ITEM 7.  IDENTIFICATION  AND CLASSIFICATION OF THE SUBSIDIARY WHICH ACQUIRED THE
         SECURITY BEING REPORTED ON BY THE PARENT HOLDING COMPANY

                  Not applicable.

ITEM 8.  IDENTIFICATION AND CLASSIFICATION OF MEMBERS OF THE GROUP

                  Not applicable.

ITEM 9.  NOTICE OF DISSOLUTION OF GROUP

                  Not applicable.

ITEM 10. CERTIFICATION

                  Not applicable

                               Page 9 of 14 pages



                                  SCHEDULE 13G
ISSUER:  Callwave, Inc.                                  CUSIP No.:  13126N 10 1


                                    SIGNATURE

            After reasonable inquiry and to the best of my knowledge and belief,
I certify that the information set forth in this statement is true, complete and
correct.

Date:  February 9, 2006

                     INSIGHT VENTURE PARTNERS IV, L.P.

                     By: Insight Venture Associates IV, LLC, its general partner

                     By: Insight Holdings Group, LLC, its managing member

                     By:            /s/Jeff Horing
                         -----------------------------------
                         Name:  Jeff Horing
                         Title: Managing Member

                     INSIGHT VENTURE PARTNERS IV (CO-INVESTORS), L.P.

                     By: Insight Venture Associates IV, LLC, its general partner

                     By: Insight Holdings Group, LLC, its managing member

                     By:            /s/Jeff Horing
                         -----------------------------------
                         Name:  Jeff Horing
                         Title: Managing Member

                     INSIGHT VENTURE PARTNERS IV (FUND B), L.P.

                     By: Insight Venture Associates IV, LLC, its general partner

                     By: Insight Holdings Group, LLC, its managing member

                     By:            /s/Jeff Horing
                         -----------------------------------
                         Name:  Jeff Horing
                         Title: Managing Member

                     INSIGHT VENTURE PARTNERS (CAYMAN) IV, L.P.

                     By: Insight Venture Associates IV, LLC, its general partner

                     By: Insight Holdings Group, LLC, its managing member

                     By:            /s/Jeff Horing
                         -----------------------------------
                         Name:  Jeff Horing
                         Title: Managing Member

                               Page 10 of 14 pages



                                  SCHEDULE 13G
ISSUER:  Callwave, Inc.                                  CUSIP No.:  13126N 10 1


                     INSIGHT VENTURE ASSOCIATES IV, LLC

                     By: Insight Holdings Group, LLC, its managing member

                     By:            /s/Jeff Horing
                         -----------------------------------
                         Name:  Jeff Horing
                         Title: Managing Member

                     INSIGHT HOLDINGS GROUP, LLC

                     By:            /s/Jeff Horing
                         -----------------------------------
                         Name:  Jeff Horing
                         Title: Managing Member

                               Page 11 of 14 pages



                                  SCHEDULE 13G
ISSUER:  Callwave, Inc.                                  CUSIP No.:  13126N 10 1


                                  EXHIBIT 2(A)

            This Statement is being filed by Insight Venture  Partners IV, L.P.,
a Delaware  limited  partnership  (hereinafter  referred  to as "IVP"),  Insight
Venture  Partners  IV  (Co-Investors),  L.P.,  a  Delaware  limited  partnership
(hereinafter  referred  to as  "IVP  Co-Investors"),  Insight  Venture  Partners
(Cayman)   IV, L.P., a Cayman Islands limited partnership  (hereinafter referred
to as "IVP  Cayman"),  Insight  Venture  Partners IV (Fund B),  L.P., a Delaware
limited partnership  (hereinafter  referred to as "IVP Fund B"), Insight Venture
Associates IV, LLC, a Delaware limited liability company  (hereinafter  referred
to as  "Associates")  and  Insight  Holdings  Group,  LLC,  a  Delaware  limited
liability  company  (hereinafter  referred  to  as  "Holdings")  each  of  whose
principal  office is located at c/o  Insight  Capital  Partners  IV,  L.P.,  527
Madison  Avenue,  10th  Floor,  New York,  New  York,  10022.  Each of IVP,  IVP
Co-Investors,  IVP Cayman and IVP Fund B (collectively referred to herein as the
"Insight Funds") is engaged in the venture capital business.  Each of Associates
and Holdings is engaged in the Venture Capital business  indirectly  through the
Insight Funds.

            Associates is the general partner of each of the Insight Funds,  and
as such may be  deemed  to be the  beneficial  owner of all  shares  held by the
Insight Funds.

            Holdings is the managing  member of  Associates,  and as such may be
deemed to be the beneficial  owner of all shares held by the Insights Funds.

                               Page 12 of 14 pages



                                  SCHEDULE 13G
ISSUER:  Callwave, Inc.                                  CUSIP No.:  13126N 10 1


                                  EXHIBIT 2(B)

                             JOINT FILING AGREEMENT

      The  undersigned  acknowledge  and agree that the  foregoing  statement on
Schedule  13G is  filed  on  behalf  of each of the  undersigned  and  that  all
subsequent amendments to this statement on Schedule 13G shall be filed on behalf
of each of the  undersigned  without the  necessity of filing  additional  joint
acquisition   statements.   The  undersigned  acknowledge  that  each  shall  be
responsible for the timely filing of such  amendments,  and for the completeness
and accuracy of the  information  concerning  him or it contained  therein,  but
shall not be responsible  for the  completeness  and accuracy of the information
concerning the other,  except to the extent that he or it knows or has reason to
believe that such information is accurate.

Dated this 9th day of February, 2006.

                     INSIGHT VENTURE PARTNERS IV, L.P.

                     By: Insight Venture Associates IV, LLC, its general partner

                     By: Insight Holdings Group, LLC, its managing member

                     By:            /s/Jeff Horing
                         -----------------------------------
                         Name:  Jeff Horing
                         Title: Managing Member

                     INSIGHT VENTURE PARTNERS IV (CO-INVESTORS), L.P.

                     By: Insight Venture Associates IV, LLC, its general partner

                     By: Insight Holdings Group, LLC, its managing member

                     By:            /s/Jeff Horing
                         -----------------------------------
                         Name:  Jeff Horing
                         Title: Managing Member

                     INSIGHT VENTURE PARTNERS IV (FUND B), L.P.

                     By: Insight Venture Associates IV, LLC, its general partner

                     By: Insight Holdings Group, LLC, its managing member

                     By:            /s/Jeff Horing
                         -----------------------------------
                         Name:  Jeff Horing
                         Title: Managing Member

                               Page 13 of 14 pages



                                  SCHEDULE 13G
ISSUER:  Callwave, Inc.                                  CUSIP No.:  13126N 10 1


                     INSIGHT VENTURE PARTNERS (CAYMAN) IV, L.P.

                     By: Insight Venture Associates IV, LLC, its general partner

                     By: Insight Holdings Group, LLC, its managing member

                     By:            /s/Jeff Horing
                         -----------------------------------
                         Name:  Jeff Horing
                         Title: Managing Member

                     INSIGHT VENTURE ASSOCIATES IV, LLC

                     By: Insight Holdings Group, LLC., its managing member

                     By:            /s/Jeff Horing
                         -----------------------------------
                         Name:  Jeff Horing
                         Title: Managing Member

                     INSIGHT HOLDINGS GROUP, LLC

                     By:            /s/Jeff Horing
                         -----------------------------------
                         Name:  Jeff Horing
                         Title: Managing Member


                               Page 14 of 14 pages