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                                                                   EXHIBIT 10.20

January 26, 2000

Mr. Richard Haverly
4 Davis Drive
Armonk, New York 10504

Dear Mr. Haverly:

We are delighted to make this offer to you to become an employee of Greenwich
Technology Partners, Inc. (the "Company") as Senior Vice President of
Operations, contained in this offering letter to you. Your anticipated start
date is January 26, 2000 and your office location will be 43 Gatehouse Road,
Stamford CT or such other location, which becomes the corporate headquarters.
This offer is valid for 15 business days from the above date.

We are very proud of our corporate culture. We believe that open communication
between the Company and its employees and treating each other fairly and with
respect are critical to our success and to creating an environment in which we
are able to enjoy our work. Consequently, we want your assurance that should
there ever come a time during your employment with the Company that you are
dissatisfied with any aspect of your employment, you will communicate such
dissatisfaction to the person to whom you directly report, or, if that is not
comfortable for you, to any other manager of the Company, including the Chief
Executive Officer.

1.   Major Terms
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     A.   Services
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          While you are employed by the Company, you will devote your entire and
          exclusive business and professional time, attention, energy, loyalty
          and skill to the business of the Company. In addition, you will use
          your reasonable efforts to preserve for the Company the goodwill of
          customers and others with whom the Company establishes business
          relationships during your employment and to advance the reputation of
          the Company. You shall comply with and perform such directions and
          duties in relation to the business and affairs of the Company
          requested of you by the Company, including:

          .    general management of the Company's business within a team of
               senior managers reporting directly to the Chairman and CEO
               including the SVP of Sales and the Chief Financial Officer;
          .    management of the Company's Managing Principals and their
               respective practice areas;
          .    management of the Company's Divisional, Regional and Branch
               Technical Managers including the oversight of engineers and
               consultants;
          .    maintenance of customer satisfaction and customer service;
          .    oversight of all aspects of service delivery to clients including
               Quality Assurance;
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                                      -2-

          .    jointly with the Sales SVP:
               .    development and expansion of account relationships and the
                    development of business with existing accounts and clients;
               .    preparation/approval of proposals, including pricing
                    policies and strategies; and
          .    identify the need for methodologies, tools and other practice
               aids and oversee their development and rollout.

     B.   Compensation and Benefits
          -------------------------

          In consideration of all of the services to be rendered by you to the
          Company, the Company will pay to you a salary of $150,000 per annum to
          be earned and paid in semimonthly installments of $6,250.00. Such
          salary shall be payable on the 15/th/ and 30/th/ day of each month in
          arrears, pro rated for the initial period worked. In addition you will
          receive Variable Compensation in accordance with the Company's
          Variable Compensation Plan. For calendar year 2000 your variable
          compensation will be equal to 50% of the full participation rate of
          0.25%. During calendar year 2000, you will be paid 0.125% of Company
          revenues on a quarterly basis (excluding revenues from the resale of
          hardware and software). Thereafter, you will participate fully in the
          Variable Compensation Plan for subsequent calendar years. The Company
          shall have the right to deduct from your compensation all taxes and
          other legally required payroll deductions and withholdings. Pursuant
          to local wage law, you are an exempt employee and therefore not
          eligible under State requirements to receive overtime pay.

          You will also receive a monthly car allowance of $250.

          You will be entitled to three (3) weeks vacation in accordance with
          our Company policy.

          You will be entitled to receive the medical, life insurance,
          disability insurance and other benefits available from time to time to
          senior executives of the Company. Currently, these benefits include:

          .    Medical: Blue Cross/Blue Shield Empire Deluxe PPO program with a
               monthly employee premium of $162.08 for family coverage (GTP
               covers the other 75% of the premium).
          .    Dental: Guardian Dental PPO with a monthly employee premium of
               $20.94 for family coverage (GTP covers the other 75% of the
               premium).
          .    Life Insurance: Guardian Life at 1 time your annual salary up to
               a maximum of $100,000. This is fully paid by the Company.
          .    Long Term/Short Term Disability: Guardian Life. This is fully
               paid by the Company.
          .    AD&D: Guardian Life up to 1 time your annual salary up to a
               maximum of $100,000. This is fully paid by the Company.
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                                      -3-

          .    401k Plan: Eligible in the quarter following your 60th day of
               employment. GTP will make a matching contribution equal to 25% of
               your savings contribution subject to a maximum contribution by
               you of $10,000 per year. Savings over 6% of your pay are not
               matched. As soon as you are enrolled you are eligible for the
               match that vests over 4 years from your participation in the
               plan.

     C.   Option/Equity
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          You will be granted not later than the Company's next regularly
          scheduled meeting of its Board of Directors an option to purchase up
          to 300,000 shares of the Company's common stock, upon approval of the
          Company's Board of Directors. The option will be issued pursuant to
          the terms of the Company's 1997 Stock Plan and a stock option
          agreement to be entered into between the Company and you (the "Option
          Agreement"). If the Board of Directors does not approve of such option
          grant, this Agreement shall be considered null and void.

          Notwithstanding anything to the contrary contained herein or in the
          Option Agreement, in the event that on or before January 25, 2001 (i)
          your employment with the Company is terminated without Cause (as that
          term is defined in the Option Agreement) or (ii) you cease to be
          employed by the Company for reasons of death or permanent disability,
          then 25% of the options granted to you in the Option Agreement (and no
          subsequent options granted to you) shall automatically vest without
          any action on your part or the Company's part.

          In addition, on or prior to the date hereof, you will be purchasing
          100,000 shares of Series E Preferred Stock of the Company at a price
          of $2.11 per share.

     D.   Employment At Will
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          You will be an employee-at-will; your employment may be terminated by
          you or the Company at any time, with or without cause. Neither this
          letter agreement, any employee handbook, or any other document of the
          Company gives you any contractual right, either express or implied, to
          remain in the employ of the Company.

     E.   Use of Company Property
          -----------------------

          You will not use the Company's premises, facilities, or equipment for
          personal purposes.

     F.   Moonlighting and Competitive Activity
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          You covenant and agree that, during non-business hours, you shall not
          engage in any activity related to, competitive with, or in the
          business of, the Company,
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                                      -4-

          without the prior written consent of the Company. Such activities
          shall include designing intranet or internet networks, network
          consulting, maintenance, repair, troubleshooting or network design
          and/or installation (a "Competitive Activity"). If you are unsure
          whether a particular activity would violate the aforesaid covenant,
          you shall seek the advice of a senior officer of the Company. You
          hereby accept said employment and agree faithfully to perform said
          duties and render said services for the term of your employment.

2.   Right to Change Pay Practices, Policies, Procedures and Benefits. The
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Company shall have the right, at any time without prior notice, to change,
modify, amend, or terminate any pay practice, employment policy or procedure, or
employment benefit plan or program in effect upon the commencement of your
employment or adopted subsequently. You will be entitled to participate on the
same basis with all other employees in similar positions of the Company in the
Company's standard benefits package generally available to other employees in
similar positions of the Company, including medical and dental coverage, a 401K
plan, short term and long term disability, and life insurance.


3.   Representations and Warranties. You represent and warrant that: you are not
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under any obligation to any third party which could interfere with your
performance under this letter agreement; and your performance of your
obligations to the Company during your employment with the Company will not
breach any agreement by which you are bound not to disclose any proprietary
information.

4.   Inventions.
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     i.   You will as soon as practicable disclose to the Company all Inventions
          (as herein defined). "Inventions" shall mean all ideas, potential
          marketing and sales relationships, inventions, research, plans for
          products and services, marketing plans, software (including, without
          limitation, source code), know-how, trade secrets, information, data,
          developments, discoveries, improvements, modifications, technology,
          and designs, whether or not subject to patent or copyright protection,
          made, conceived, expressed, developed, or actually or constructively
          reduced to practice by you solely or jointly with others during your
          employment with the Company, which refer to, are suggested by, or
          result from any work which you may do during your employment, or from
          any information obtained from the Company.

     ii.  The Inventions shall be the exclusive property of the Company, and are
          hereby assigned by you to the Company; the Company shall have the
          exclusive right to use the Inventions for all purposes without
          additional compensation to you. At the Company's expense, you will
          assist the Company in every proper way to protect the Inventions
          throughout the world, including, without limitation, executing in
          favor of the Company patent, copyright, and other applications and
          assignments relating to the Inventions.
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                                      -5-

5.   Confidential Information.
     ------------------------

     i.   You will not disclose, give, sell, publish or otherwise use, either
          during your employment by the Company or after the termination of your
          employment for a period of one year, except in the performance of your
          duties for the benefit of the Company, any Confidential Information
          (as herein defined). "Confidential Information" shall mean, but not be
          limited to, all of the Company's proprietary information, technical
          data, technology, process, trade secrets, and know-how, other
          intellectual property rights, strategies, financial statements or
          other financial information, forecasts, operations, business plans,
          prices, discounts, products, product specifications, designs, plans
          data, ideas or information contained in the Company's Business
          Strategy Overview and Career Advancement Manual which is disclosed to
          you, which you may acquire or develop, or which you may observe in the
          course of your employment by the Company and which at the time of
          disclosure is not previously known by you and not known or used by
          others in the trade generally, does not become generally available to
          the trade through no fault of yours, and does not become rightfully
          available to you on a non-confidential basis from a source other than
          the Company, including, without limitation, research, product plans,
          customer lists, markets, software, developments, inventions,
          processes, formulas, technology, designs, drawings, marketing and
          other plans, and financial data and information. "Confidential
          Information" shall also mean information received by the Company from
          customers of the Company or other third parties subject to a duty to
          keep confidential and financial, pricing, and credit information
          regarding customers, clients, or vendors of the Company. Upon
          termination of your employment, you shall promptly deliver to the
          Company, in whatever form or medium, all files, drawings, blueprints,
          specifications, reports, notebooks, and other materials containing any
          Confidential Information which are in your possession or control.
          Notwithstanding anything contained in this paragraph, Confidential
          Information shall not include any information, technical data,
          technology, process, trade secrets, know-how, other intellectual
          property rights or strategies which you have in your possession prior
          to your employment with the Company. For the purposes of this
          Agreement, Confidential Information shall be only that information,
          which Greenwich Technology Partners can demonstrate, came from their
          sources and no other sources. Greenwich Technology Partners realizes
          that Mr. Haverly has worked in a similar industry for approximately
          thirty years and has substantial prior technical data, intellectual
          property and strategies in his possession at the time of his
          employment.

     ii.  You shall not discuss with, or disclose to, other employees of the
          Company, the terms of your Offer Package, including, but not limited
          to, compensation, grant of options or other special arrangements. Such
          information shall be considered Confidential Information, and
          disclosure of such Confidential Information shall be grounds for your
          dismissal from the Company.
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                                      -6-

6.   Restrictive Covenants.
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     A.   Covenants Against Competition and Solicitation.
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          From the date hereof until the period equal to the shorter of (A) one
          year following the date of termination of your employment with the
          Company or (B) the period equal to the number of complete months of
          your employment with the Company up to a period of twelve complete
          months, without the prior written consent of the Company, you will not
          directly or indirectly:

          i.   persuade, or attempt to persuade any customer or client of the
               Company who was a customer or client of the Company on the date
               of your termination to cease doing business with the Company, or
               to reduce the amount of business such customer or client does
               with the Company in the areas specifically noted in Section 1.F
               hereof;

          ii.  persuade, or attempt to persuade any potential customer or client
               to which the Company has delivered a formal written proposal in
               the six months preceding your termination not to do business with
               the Company in the areas and scope of work specified by the
               formal proposal (activities in proposals that are restricted are
               limited to those specifically noted in Section 1.F hereof);

          iii. solicit for yourself or any other person other than the Company
               the business of any person, individual, corporation, partnership,
               trust, joint venture, business or incorporated organization which
               is, at the time of your termination, a current customer or client
               of the Company. If the target company has annual revenues greater
               than $100 million, this restriction does not apply. Such
               limitation on solicitation is only to areas specifically noted in
               Section 1.F hereof; or

          iv.  persuade, or attempt to persuade any employee of the Company
               to leave the employ of the Company.

7.   Injunctive Relief and Severability.
     ----------------------------------

     i.   You agree that the remedy at law for any breach of the provisions of
          this letter agreement shall be inadequate and the Company shall be
          entitled to injunctive or other equitable relief in addition to any
          other remedy it might have.

     ii.  The Company and you agree and acknowledge that the covenant not to
          compete is made in consideration of substantial compensation payable
          under this letter agreement. Should a court determine that the
          duration, scope, or geographic areas in such covenant are not
          reasonable, such restrictions shall be interpreted,

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                                     -7-

          modified, or rewritten to include as much of such duration, scope, or
          geographic areas as will render such restrictions valid and
          enforceable.

     iii. The Company and you intend to and do hereby confer jurisdiction to
          enforce this letter agreement upon the courts of the State of New
          York.

8.   Severability. In the event any of the provisions of this letter agreement
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shall be held by a court or other tribunal of competent jurisdiction to be
unenforceable, the other provisions of this letter agreement shall remain in
full force and effect.

9.   Survival. All terms and conditions of this letter agreement which should by
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their nature survive the termination of your employment with the Company shall
so survive.

10.  Governing Law. This letter shall be governed by, construed and enforced in
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accordance with the internal laws of the State of New York governing agreements
made and to be fully performed therein, without giving effect to conflict of law
principles.

11.  Notices. All notices, requests, consents and other communications required
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or permitted hereunder shall be in writing and shall be hand delivered or mailed
by certified or registered mail, return receipt requested, addressed as follows:

     i.   if to the Company, at Greenwich Technology Partners, Inc., 43
          Gatehouse Road, Stamford, CT 06902, Attention: Director of Legal
          Affairs.

     ii.  if to you, at the address set forth above or in any such case, at such
          other addresses as may have been furnished to any party by the other
          party in writing in the manner herein provided. Any notice or other
          communication so addressed and so mailed shall be deemed to have been
          given when received, and if hand delivered shall be deemed to have
          been given when delivered.

The address for such notices may be changed from time to time by written notice
given in the manner provided for herein.

12.  Waivers and Modifications. This letter agreement may be modified, and the
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rights and remedies of any provision hereof may be waived, only in writing,
signed by each of the Company, and you. No waiver by either party of any breach
by the other of any provision hereof shall be deemed to be a waiver of any later
or other breach thereof or as a waiver of any such or other provision of this
letter agreement. This agreement sets forth all of the terms of the
understandings between the parties with reference to the subject matter set
forth herein may not be waived, changed, discharged or terminated orally or by
any course of dealing between the parties, but only by an instrument in writing
signed by the party against whom any waiver, change, discharge or termination is
sought. Each of the Company and you hereby acknowledges and agrees that any
prior arrangements, agreements or understandings relating to your employment
with the Company and/or any of its affiliates is hereby terminated and
extinguished in its entirety.
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13.  Assignment. This Agreement shall be binding upon and inure to the benefit
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of the Company and its successors and assigns. This Agreement is not assignable
by you and your right to receive payment for your services is hereby expressly
agreed to be non-assignable and nontransferable, except as otherwise
specifically provided herein.

Sincerely,

/s/ Dennis M. Goett

Dennis M. Goett
Chief Financial Officer


I have carefully read the terms and conditions of the above and acknowledge and
accept the terms and conditions of this letter agreement.

Please sign, date and return this offer letter prior to your state date.

Signature: /s/ Richard C. Haverly
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           Richard Haverly

Date:      1/26/00
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