<PAGE>

                                                                    Exhibit 10.7

                               FIRST AMENDMENT TO
                       1899 WYNKOOP OFFICE BUILDING LEASE
                       ----------------------------------

     THIS FIRST AMENDMENT TO 1899 WYNKOOP OFFICE BUILDING LEASE (the "First
Amendment") is made this 31st day of January, 2002, between 1899 WYNKOOP, LLC,
as successor to Centennial Venture I, LLC, ("Landlord") and WEBB INTERACTIVE
SERVICES, INC., ("Tenant").

                                   WITNESSETH

     WHEREAS, Tenant entered into a 1899 Wynkoop Office Building Lease (the
"Lease") dated December 8, 1999 with Centennial Venture I, LLC for certain
premises consisting of approximately 21,398 rentable square feet of space known
as Suite 600, at 1899 Wynkoop Street, Denver, Colorado 80202 ("the Building");

     WHEREAS, Landlord and Tenant now desire to, among other things, amend the
Lease to shorten the Term, decrease the Base Rent and increase the Expense Stop;

     WHEREAS, the Lease and this First Amendment are collectively referred to as
the "Lease";

     NOW, THEREFORE, in consideration of the mutual promises and covenants
contained herein, the receipt and sufficiency of which are hereby acknowledged,
Landlord and Tenant hereby agree to amend the Lease effective as of December 31,
2001 as follows:

     1. Term: Paragraph 2(a) of the Lease is hereby amended to read in its
        ----
entirety as follows:

          The Term of this Lease shall commence on January 1, 2002 (the
          "Commencement Date") and shall terminate at 12:00 midnight on August
          31, 2004, unless sooner terminated pursuant to the terms of the Lease.

     2. Base Rent: Paragraph 3 of the Lease is hereby amended to read in its
        ---------
entirety as follows:

          Tenant shall pay to Landlord, rent for the Premises in accordance with
          the following schedule (hereinafter "Base Rent"):

                                            MONTHLY         ANNUAL
                  PERIOD                   BASE RENT      BASE RENT
     February 1, 2002 to August 3, 2004    $35,000.00    $420,000.00

All installments of Base Rent shall be payable in advance, on the first (1st)
day of each calendar month during the term hereof. Base Rent for the first and
last months of the term hereof shall be prorated based upon the number of days
during each of said months that the Lease term was in effect. The first month's
Base Rent shall be due and payable upon the Commencement Date.
<PAGE>

All Base Rent shall be paid without notice, demand, deduction, or offset, at the
office of Landlord or to such other person or at such other place as Landlord
may designate in writing.

     3. Expense Stop: Paragraph 5(a)(1) of the Lease is hereby amended to change
        ------------
the reference to "$6.50 per rentable square foot of the Building" to "$7.85 per
rentable square foot of the Building." Notwithstanding anything in this First
Amendment to the contrary, Tenant shall remain obligated to pay for its share of
any Operating Expense Differential for the 2001 calendar year based upon the
$6.50 Expense Stop.

     4. Certificate of Deposit. Tenant agrees that if it does not rescind this
        ----------------------
First Amendment in accordance with Paragraph 6 hereof, that Landlord, as
consideration for this First Amendment, is authorized at anytime after the close
of business on January 31, 2002, to draw the full amount of the Certificates of
Deposit ($475,000.00) held by Wells Fargo Bank pursuant to that certain
Certificate of Deposit Pledge Agreement between Landlord and Tenant, and
consented to by Wells Fargo Bank. Tenant further agrees to execute and deliver
to Landlord and Wells Fargo Bank any and all documents requested by either
Landlord or Wells Fargo Bank to effectuate the transfer of the Certificates of
Deposit to Landlord. Landlord is hereby authorized to instruct Wells Fargo Bank
to transfer the Certificates of Deposit to Landlord in accordance with this
Paragraph notwithstanding that no event of default has occurred. Landlord agrees
that upon receipt of the Certificates of Deposit that the Lease shall be amended
to delete Section 42 in its entirety.

     5. Assignment. This First Amendment is subject to and contingent upon the
        ----------
execution and delivery of the Assignment and Assumption of the Lease, as
amended, to Jabber, Inc., the Tenant Estoppel Certificate, and Consent to
Assignment, which Assignment, Estoppel and Consent are attached hereto as
Exhibits A, B and C and by this reference incorporated herein.

     6. Option to Rescind. Landlord hereby grants Tenant the option to rescind
        -----------------
this First Amendment; provided that, this option shall only be exercisable by
Tenant if it is not otherwise in default of the Lease. In order to exercise this
option, Tenant shall deliver written notice to Landlord of Tenant's exercise of
this option on or before the close of business (5:00 p.m. MST) on January 31,
2002. If Tenant fails to deliver written notice in accordance with this
Paragraph 6 or fails to pay the expenses set forth infra, this option shall
                                                   -----
lapse and be null and void, notwithstanding Tenant's attempt to exercise the
same. As consideration for Tenant's rescission of this First Amendment, Tenant
hereby agrees to reimburse Landlord for all of its actual expenses related to
the negotiation, preparation and termination of this First Amendment, including,
but not limited to all professional fees and out-of-pocket expenses incurred by
Landlord. Tenant shall pay such actual expenses to Landlord within ten (10) days
of receipt of Landlord's invoice for the same. In the event Tenant properly
exercises this option to rescind and pays the actual expenses, this First
Amendment shall be null and void and of no further force and effect.

     7. Brokerage: Landlord and Tenant each covenant and represent that it has
        ---------
negotiated this First Amendment directly with the other, and has not acted by
implication to authorize or authorized any real estate agent, broker, or
salesman to act for it in these negotiations. Tenant agrees to indemnify and
hold harmless Landlord from any and all claims by any real estate broker or
salesman for a commission or finder's fee arising out of or related to Tenant's
acts or omissions in entering into this First Amendment.

                                      -2-
<PAGE>

     8. Ratification: Except as specifically amended by the terms of this First
        ------------
Amendment, the terms and conditions of the Lease, shall remain in full force and
effect and are republished and Landlord and Tenant each ratifies and confirms
the same. In the event of a conflict between the terms of this First Amendment
and the Lease, the terms of this First Amendment shall control.

     IN WITNESS WHEREOF, the parties hereto have executed this First Amendment
to 1899 Wynkoop Office Building Lease as of the day and year first above
written.

                                          LANDLORD:

                                          1899 WYNKOOP, LLC


                                          By:    /s/ Randy Nichols
                                              ----------------------------------

                                          Title: General Manager
                                                 -------------------------------


                                          TENANT:


                                          WEBB INTERACTIVE SERVICES, INC


                                          By:    /s/ William R. Cullen
                                              ----------------------------------

                                          Title: CEO
                                                 -------------------------------

ATTEST:


By:   /s/ Lindley S. Branson
   ----------------------------

                                      -3-
<PAGE>

                       ASSIGNMENT AND ASSUMPTION OF LEASE
                       ----------------------------------

     This Assignment and Assumption of Lease ("Assignment") is made and entered
into this 16th day of January, 2002.

     1. Assignment. For good and valuable consideration the receipt and
        ----------
sufficiency of which are hereby acknowledged, WEBB INTERACTIVE SERVICES, INC., a
Colorado corporation ("Assignor") hereby assigns and transfers to JABBER, INC.,
a Delaware corporation ("Assignee") all Assignor's right, title and interest in
and to that certain Lease dated November 22, 1999, as amended by a First
Amendment dated even date herewith, between 1899 WYNKOOP, LLC, as successor to
CENTENNIAL VENTURE I, LLC, ("Lessor") and Assignor ("the Lease") for those
certain premises (the "Premises") described in the Lease (approximately 21,398
rentable square feet of office space known as Suite 600); provided that, this
Assignment shall be effective at the close of business On January 31, 2002, but
only if Assignor does not rescind the First Amendment.

     2. Assumption. Assignee hereby accepts the assignment of the Lease made
        ----------
herein, assumes the Lease and all rights and obligations of Assignor thereunder,
and agrees to look to 1899 WYNKOOP, LLC, as successor to CENTENNIAL VENTURE I,
LLC, as Lessor thereunder. Assignee covenants and agrees to make all payments
and to perform all duties and obligations required of the Lessee from and after
the date of this Assignment at the times and in the manner such payments and
performances are to be paid and performed under the terms of the Lease;
provided, however, that to the extent there are additional Operating Expenses
which are due for the calendar year 2001 for the period prior to this Assignment
& Assumption, Assignee agrees that it shall be responsible for and pay such
additional expenses.

     3. Lessor's Consent. It is understood and agreed that this Assignment is
        ----------------
subject to the terms and conditions of Lessor's Consent to Assignment.

     IN WITNESS WHEREOF, the undersigned have executed this Assignment and
Assumption of Lease as of the day and year first above written.

ASSIGNOR:  WEBB INTERACTIVE               ASSIGNEE:  JABBER, INC., a Delaware
SERVICES, INC., a Colorado corporation    corporation


By:   /s/  William R. Cullen              By:   /s/ Gwenael Hagen
     ---------------------------------         ---------------------------------

Name: William R. Cullen                   Name: Gwenael Hagen
      --------------------------------          --------------------------------

Its:  CEO                                 Its:   CFO
     ---------------------------------         ---------------------------------

Date: January 30, 2002                    Date: January 30, 2002
      --------------------------------          --------------------------------
<PAGE>

                              CONSENT TO ASSIGNMENT

     This Consent to Assignment (this "Consent") is made as of January 31, 2002,
by and between 1899 Wynkoop, LLC, as successor to CENTENNIAL VENTURE I, LLC,
("Lessor"), and WEBB INTERACTIVE SERVICES, INC., a Colorado corporation
("Assignor"), and JABBER, INC., a Delaware corporation ("Assignee").

                                    RECITALS
                                    --------

     A. Lessor and Assignor have entered into that certain Lease dated December
8, 1999, as amended by a First Amendment to 1899 Wynkoop Office Building Lease
dated even dated herewith (collectively the "Lease"), wherein Lessor leased to
Assignor certain premises comprising that certain building known as 1899 Wynkoop
and located at 1899 Wynkoop Street, Suite 600, Denver, Colorado 80202 (the
"Premises"), and more particularly described in the Lease.

     B. Assignor desires to assign to Assignee all of its right, title, interest
and estate in, to arid under the Lease.

     C. Assignor desires to obtain Lessor's consent to the Assignment.

     NOW, THEREFORE, Lessor hereby consents to the Assignment, such consent
being subject to an upon the following terms and conditions to which Assignor
and Assignee hereby agree:

     1. All terms not otherwise defined in this Consent shall have the meanings
set forth in the Lease unless the context clearly indicates otherwise. In the
event of any conflict between the Assignment and this Consent, the provisions of
this Consent shall control.

     2. This Consent shall not be effective and the Assignment shall not be
valid or binding on Lessor unless and until a fully executed original
counterpart of the Assignment in the form attached hereto is delivered to
Lessor, and a fully executed original Estoppel Certificate in the form attached
hereto is delivered to Lessor.

     3. This Consent is expressly contingent upon Assignor not rescinding the
First Amendment and the receipt by Lessor of Four Hundred Seventy Five Thousand
and no/100 Dollars ($475,000.00) represented by certain Certificates of Deposit
held by Wells Fargo Bank. In the event Assignor rescinds the First Amendment or
fails to cause the Four Hundred Seventy Five Thousand and no/100 Dollars
($475,000.00) to be paid to Lessor, this Consent shall be null and void ab
                                                                        --
initio.
------

     4. Assignee does hereby expressly assume and agree to be bound by and to
perform and comply with, for the benefit of Lessor, each and every obligation of
Assignor under the Lease.

     5. The acceptance of rents by Lessor from Assignee or anyone else liable
under the Lease shall not be deemed a waiver by Lessor of any provisions of the
Lease.

     6. Landlord acknowledges to Assignee that as of the date of this Consent,
the Assignor is not in default of any obligations under the Lease.
<PAGE>

     7. This consent shall not constitute a consent to any subsequent subletting
or assignment and shall not relieve Assignee or any person claiming under or
through Assignee of the obligation to obtain the consent of Lessor, pursuant to
Paragraph 17 of the Lease, to any future assignment or sublease. Lessor
acknowledges that Assignee intends to sublet space to Assignor and hereby waives
the requirements of Paragraph 17 of the Lease as it relates to a sublease
between Assignee and Assignor; provided that: (a) the sublet shall be evidenced
on Landlord's standard sublease form; (b) Assignor shall provide Landlord with
satisfactory evidence of insurance; and (e) this waiver shall not constitute a
wavier of the requirements of Paragraph 17 of the Lease to any future sublease
or assignment.

     8. Lessor may consent to subsequent sublettings and assignments of the
Lease without notifying Assignor or anyone else liable under the Lease and
without obtaining their consent (other than the consent of Assignee if it is
stilt liable under the Lease) and such action shall not relieve such persons
from liability.

     9. Nothing contained herein shall be deemed or construed to modify, waive,
impair or affect any of the covenants, agreements, terms provisions or
conditions contained in the Lease.

     10. This Consent may be executed in any number of counterparts, each of
which shall be deemed an original, but all of which when taken together shall
constitute but one and the same instrument.

     IN WITNESS WHEREOF, Lessor, Assignor and Assignee have caused their duly
authorized representatives to execute this Consent as of the date first above
written.

ASSIGNOR: WEBB INTERACTIVE                LESSOR:  1899 WYNKOOP, LLC, as
SERVICES, INC., a Colorado corporation    successor to CENTENNIAL VENTURE I,
                                          LLC, a Colorado limited liability
                                          company


By:   /s/  William R. Cullen              By:   /s/ Randy Nichols
     ---------------------------------         ---------------------------------

Name: William R. Cullen                   Name: Randy Nichols
      --------------------------------          --------------------------------

Its:  CEO                                 Its:  General Manager
     ---------------------------------         ---------------------------------

Date: January 30, 2002                    Date: January 31, 2002
      --------------------------------          --------------------------------


ASSIGNEE: JABBER, INC., a Delaware
corporation


By:   /s/ Gwenael Hagen
     ---------------------------------

Name: Gwenael Hagen
      --------------------------------

Its:  CFO
     ---------------------------------

Date: January 30, 2002
      --------------------------------

                                      -2-