CERTAIN INFORMATION IN THIS EXHIBIT HAS BEEN OMITTED AND FILED SEPARATELY WITH
THE COMMISSION. CONFIDENTIAL TREATMENT HAS BEEN REQUESTED WITH RESPECT TO THE
OMITTED PORTIONS. ASTERISKS DENOTE OMISSIONS.

                                                                   EXHIBIT 10.79

                                                                  EXECUTION COPY

                               @VENTURES III, L.P.

                        AMENDMENT TO MANAGEMENT CONTRACT

     THIS AMENDMENT dated as of June 7, 2002, to the Management Contract dated
as of August 7, 1998 (the "Management Contract"), between @Ventures III, L.P., a
Delaware limited partnership (the "Partnership"), and @Ventures Management, LLC,
a Delaware limited liability company (the "Company"), shall be and become
effective on the Amendment Effective Date (as that term is defined in the
Agreement of Limited Partnership of the Partnership (as amended and in effect
from time to time, the "Agreement").

     For good and valuable consideration, the receipt and sufficiency of which
is hereby acknowledged, the Partnership and the Company hereby agree to amend
the Management Contract as follows:

1.   Amendment to Section 4.  Section 4 of the Management Contract is hereby
     ----------------------
amended by (a) deleting the last sentence thereof, and (b) by adding, at the end
thereof, the following paragraph:

          "Notwithstanding the foregoing or any provision of this Contract to
     the contrary, with respect to all periods from and after February 1, 2002
     through [***], the Company hereby waives [***] management fees; provided
     however, that if, pursuant to Section 11.1(1)(y) of the Agreement, the term
     of the Partnership is extended by the Limited Partners through [***]
     following a termination of @Ventures Expansion Fund, L.P. ("Expansion
     Fund") prior to [***], the Partnership shall pay to the Company a
     management fee equal to the amount of the management fee which would have
     been payable by Expansion Fund to @Ventures Expansion Management LLC for
     the period between the date of the termination of Expansion Fund and [***]
     (i.e., fees at an annualized rate of $[***], but reduced by amounts paid by
     Expansion Fund on account of periods preceding the date of termination of
     the Expansion Fund), any such fee to be payable in advance, in a lump sum,
     at the time specified in Section 11.1(1)(y) of the Agreement. If, pursuant
     to Section 11.1(1)(x) of the Agreement, the term of the Partnership is
     extended, the management fee for any such extension period payable to the
     Company shall be an amount mutually acceptable to the Company and the
     Partnership (any such Partnership approval to require the consent of
     Two-Thirds in Interest of the Limited Partners), but in no event shall such
     fees exceed $[***] per year, and any such management fee shall be payable
     in semi-annual installments on January 1 and July 1 of each year during the
     extension period."

2.   Amendment to Section 5.  Section 5 of the Management Contract is hereby
     ----------------------
amended by adding, at the end thereof, the following sentence:





     "Notwithstanding the foregoing, any amount which, pursuant to this Section
     5, is to be retained by the Company and credited against the management fee
     payable by the Partnership in respect of any period from and after the
     Amendment Effective Date through [***], shall, if the Partnership is not at
     the time paying a management fee equal to or greater than such amount,
     instead be paid to the Partnership."

3.   Amendment to Section 6.  Section 6 of the Management Contract is hereby
     ----------------------
amended by adding, at the end thereof, the following sentence:

     "Notwithstanding any provision of the Agreement or this Contract to the
     contrary, this Contract shall automatically terminate on the last day of
     the Partnership term determined in accordance with Section 2.5 of the
     Agreement."

                            [Signature page follows.]


                                      - 2 -



          IN WITNESS WHEREOF, the Partnership and the Company have caused this
     Amendment be signed (in counterparts) as of the date first above written.

                                        @VENTURES III, L.P.

                                        By:  @Ventures Partners III, LLC,
                                             its general partner

                                        By: /s/ Peter H. Mills
                                            ---------------------

                                        Name: Peter H. Mills
                                              --------------------------
                                              Authorized Managing Member


                                        @VENTURES MANAGEMENT, LLC


                                        By: /s/ Peter H. Mills
                                            ------------------

                                        Name: /s/ Peter H. Mills
                                              ------------------
                                              Authorized Member

                                      - 3 -