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                                                                   EXHIBIT 10.13

PRIVATE AND CONFIDENTIAL

March 6, 2003


Presby Corp.
5910 North Central Expressway
Suite 1710
Dallas, Texas
75206

Attention:      Terence Walts, CEO and President

Dear Sirs:

Re:     Advisory Engagement

        Verus Support Services Inc., on its own and, if it deems necessary, on
        behalf of its affiliated companies (the "Advisor"), hereby agrees to be
        appointed as a non-exclusive Advisor for and on behalf of Presby Corp.
        (the "Company") to provide fiscal, financial and management advisory
        services (the "Advisory Services") that will include but not be limited
        to, discussion and recommendations on the following matters:

                1.      Identify critical success factors for the overall
                        business plan.
                2.      Work with Company to establish market awareness in North
                        America, Europe and selected launch countries as
                        assigned during the term of this Agreement.
                3.      Consult with management and any PR/IR firms engaged by
                        the Company to develop the appropriate press and
                        investor relations material.
                4.      Introduce the Company to influential stock market
                        participants including stock brokerage firms, Fund
                        Managers and Investment Counselors.
                5.      Coordinate on-going communications with current and
                        potential investors.
                6.      Analyze the Company's capital structure and recommend an
                        appropriate structure to meet the long term needs of the
                        Company.
                7.      Develop long range financing plans and structures to
                        ensure the Company has the strength to support its
                        business.
                8.      Assist in the preparation of documentation for any
                        anticipated financial offerings.
                9.      Participate in the execution of the funding programs.
                10.     Coordinate the activities of other financial advisors
                        retained by the Company.
                11.     If required, help establish merger and acquisition
                        rationale and criteria, screen candidates, make
                        recommendations.

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March 6, 2003
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The Advisor shall provide advice and direction to the Company, but under no
circumstances shall the Advisor be held liable, for any reason whatsoever, for
the accuracy of any of the third party information used in the Advisory
Services, nor shall it be liable for any information furnished by the Company.
Further, the Company shall indemnify the Advisor as provided in Schedule "A"
attached hereto. In addition, the Advisor acknowledges that the Company shall be
under no obligation to accept or implement any advice or direction provided to
it by the Advisor, and that such advice and direction shall constitute
recommendations only, subject to acceptance and implementation by the Company in
its sole discretion.

TERM AND TERMINATION:

The term of this agreement shall commence upon the later of (i) the closing (the
"RPO Closing") of the transactions contemplated by the Amended and Restated
Summary of Terms and Conditions for Merger and Private Placement dated February
3, 2003 (as it may be amended or modified from time to time, the "RPO Term
Sheet"), by and between the Company and VERUS, or (ii) in connection with the
private placement contemplated by the RPO Term Sheet, the delivery by the
Advisor of the Verus Contingent Subscription (as defined in the RPO Term Sheet)
in form and substance satisfactory to the Company. If the RPO Closing has not
occurred by March 15, 2003, or if the Advisor has not provided the Verus
Contingent Subscription by such date, this agreement shall terminate prior to
commencement, and neither party shall have any further obligation to the other
hereunder.

Following commencement of the term, this agreement shall expire upon the date
twelve (12) months after the date of the RPO Closing, unless extended or earlier
terminated as set forth herein. This agreement may be terminated by either party
upon 30 days' prior written notice at any time for any reason, or by the Company
upon 15 days' prior written notice "for cause," which notice shall specify the
effective date, and in the case of any termination "for cause," the reason(s)
therefor, of such termination. On such effective date, this Agreement shall
terminate unless, in the case of any termination "for cause," the Advisor shall
have theretofore remedied or cured its breach in all material respects under
this agreement. For purposes of this agreement, "for cause" shall mean a
material breach of any representation, warranty or other term of this agreement,
or willful misconduct or gross negligence by a party in the performance of its
duties hereunder, or any failure by the Advisor to perform its obligations under
the Verus Contingent Subscription. In the event of any termination of this
agreement prior to the expiration of the term, the Company shall continue to pay
the fees and expenses due to Advisor hereunder, unless such termination is "for
cause," in which event, the Company's obligation to make such payments shall
terminate with such termination.

BOARD OBSERVATION RIGHT AND INFORMATION RIGHTS:

The Advisor shall have the right to appoint one representative as an observer
who shall have the right to receive notice of, and attend any meetings of the
Board of Directors of the Company, and be furnished all Board-related
information otherwise available to all the Company's directors.

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March 6, 2003
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Such right to appoint one representative as an observer to the Board of
Directors shall continue for 24 months after the date of the RPO Closing.

FEES:

For the services outlined above, the Company will remit to the Advisor, a fee of
(US)$15,000 per month, for the term of this agreement, payable monthly in
advance with the first payment due upon commencement of the term hereof. To the
extent that reasonable out-of-pocket expenses are incurred by the Advisor
pursuant to this Advisory Engagement, the Advisor shall submit invoices to the
Company, accompanied by such supporting documentation as the Company shall
reasonably request. If any proposed expense exceeds $500, the Advisor shall not
be entitled to reimbursement for such expense unless such expense had been
approved in advance by the Company. Following receipt by the Company of any such
requests for reimbursement, the Company shall promptly review such requests and
if no further information is required, make such reimbursement within 15 days of
receipt by the Company. These expenses will be limited to a maximum of
(US)$10,000 per quarter based on an approved budget submitted to the Company by
the Advisor, in advance.

REPRESENTATIONS AND WARRANTIES:

The Company represents and warrants to Advisor that the Company will cooperate
with Advisor so as to permit the Advisory Services to be performed by Advisor
under this agreement to be performed in a manner consistent with the applicable
state and federal securities laws and regulations of the United States; and that
all information and statements provided by the Company will be true and correct
in all material respects, and will not be misleading or violate the anti-fraud
provisions of the Securities Exchange Act of 1934, as amended (the "Exchange
Act"), in any material respect.

Advisor further represents and warrants to the Company that: Advisor will not
cause or knowingly permit any action to be taken in connection with the
performance of its Advisory Services which violates the applicable federal or
state laws and regulations of the United States, including applicable securities
laws and regulations; Advisor will cooperate with the Company so as to permit
the Advisory Services to be performed by Advisor under this agreement to be
performed in a manner consistent with the applicable state and federal laws and
regulations of the United States and the applicable provincial and federal laws;
and that all information and statements provided by Advisor will be true and
correct in all material respects, and will not be misleading or violate the
anti-fraud provisions of the Exchange Act in any material respect. Without
limiting the generality of the foregoing, Advisor represents and warrants that,
in connection with its participation in the transactions contemplated by the RPO
Term Sheet, it has fully disclosed, or shall disclose, to all parties the
benefits to be obtained by it under this agreement, and that in connection with
the performance of its Advisory Services under this agreement, it has disclosed,
or shall disclose, to all parties its participation in the transactions
contemplated by the RPO Term Sheet.

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March 6, 2003
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CONFIDENTIAL AND PROPRIETARY INFORMATION:

Advisor recognizes and acknowledges that by reason of its service to the
Company, Advisor will have access to confidential information of the Company and
its affiliates, including, without limitation, information and knowledge
pertaining to products and services offered, inventions, innovations, designs,
ideas, plans, trade secrets, financial data, proprietary information,
advertising, distribution and sales methods and systems, and relationships
between the Company and its affiliates and customers, clients, suppliers and
others who have business dealings with the Company and its affiliates
("Confidential Information"), which is not generally known in the industry and
for which the Company notifies Advisor is confidential. During the term and for
a period of two (2) years thereafter, Advisor shall (i) protect such
Confidential Information from disclosure, and (ii) not use such Confidential
Information for any purpose other than in connection with the Advisory Services
to be provided under this agreement, and that any use by the Advisor and/or
third parties associated with the Advisor to materially benefit from such
Confidential Information other than in connection with the Advisory Services
indicated within this agreement, shall serve as basis for termination for cause.
Upon expiration or termination of this agreement, Advisor will return all
tangible materials, whether delivered to or prepared by Advisor, containing
Confidential Information to the Company.

INDEPENDENT CONTRACTOR:

With respect to the Advisory Services under this agreement, Advisor, for all
purposes, shall be and act as an independent contractor, advisor, consultant
and, if applicable, a private placement agent for the Company, and shall not be
or act as an "underwriter," co-venturer, employee, agent, or attorney of the
Company. Advisor shall not have authority, and shall not represent itself as
having authority, to enter into any agreement or incur any obligation on behalf
of the Company.

RENEWAL:

This agreement, without any action by either the Company or Advisor, shall
automatically expire at the end of the 12 month term, unless both parties agree
in writing to renew this agreement at or prior to the expiration of the initial
12 month term.

MISCELLANEOUS:

This agreement shall be construed and governed in accordance with the laws of
the State of New York without giving effect to any conflict of laws provisions.
Advisor and the Company hereby consent to the personal jurisdiction of the State
and County of New York and waive any objections to such forum and venue. The
prevailing party in any legal action brought under this agreement shall be
entitled to immediately recover all legal fees and costs.

No modification or waiver of any provision of this agreement shall be valid
unless it is in writing and signed by the party against whom it is sought to be
enforced. No waiver at any time of any

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March 6, 2003
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provision of this agreement shall be deemed a waiver of any other provision of
this agreement at that time or a waiver of that or any other provision at any
other time.

This agreement constitutes the entire agreement between the parties with respect
to the subject matter hereof. Any and all prior agreements and understandings,
whether written or oral, are superseded hereby and are deemed null and void and
of no effect. The parties are not bound by any agreements, understandings,
conditions or inducements otherwise than are as expressly referenced, set forth,
or stipulated hereunder.

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

The headings and captions of the various subdivisions of this agreement are for
convenience of reference only and shall in no way modify or affect the meaning
or construction of any of the terms or provisions hereof.

No failure or delay by a party hereto in exercising any right, power or remedy
under this agreement, and no course of dealing among the parties hereto, shall
operate as a waiver of any such right, power or remedy of the party. No single
or partial exercise of any right, power or remedy under this agreement by a
party hereto, nor any abandonment or discontinuance of steps to enforce any such
right, power or remedy, shall preclude such party from any other or further
exercise thereof or the exercise of any other right, power or remedy hereunder.
The election of any remedy by a party hereto shall not constitute a waiver of
the right of such party to pursue other available remedies. No notice or demand
on a party not expressly required under this agreement shall entitle the party
receiving such notice or demand to any other or further notice or demand in
similar or other circumstances or constitute a waiver of the rights of the party
giving such notice or demand to any other or further action in any circumstances
without such notice or demand.

This agreement shall inure to the benefit of the respective successors and
assigns of the parties hereto and their successors, assigns and representatives,
and the obligations and liabilities assumed in this agreement by the parties
hereto shall be binding upon their respective successors and assigns.
Notwithstanding anything to the contrary in this agreement, Advisor may not
assign its rights or obligations hereunder without the prior written consent of
the Company.

This agreement does not create, and shall not be construed as creating, rights
enforceable by any person or entity not a party hereto.

If this agreement accurately reflects your understanding of the terms of our
agreement and you agree to be legally bound thereby, please execute this
agreement (in counterparts, if necessary) where indicated below and return a
copy thereof to Verus Support Services Inc.

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March 6, 2003
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Yours very truly,

VERUS SUPPORT SERVICES INC.


Per: /s/ Andrew Merkatz
    ---------------------------------------
       Authorized Signing Officer


The foregoing accurately reflects the terms of the transaction that we hereby
agree to enter into and the undersigned agrees to be legally bound hereby.

Accepted this 6th day of March 2003.

PRESBY CORP

Per: /s/ Mark A. Cox
    ---------------------------------------
       Authorized Signing Officer

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                                  SCHEDULE "A"

Presby Corp (the "Indemnitor") hereby agrees to indemnify and hold Verus Support
Services Inc. and/or any of their respective affiliates (hereinafter referred to
as the "Advisor") and each of the directors, officers, employees and partners of
the Advisor (hereinafter referred to as the "Personnel" or "Senior Consultants")
harmless from and against any and all expenses, losses (other than loss of
profits), claims, actions, damages or liabilities ("Damages"), whether joint or
several (including the aggregate amount paid in reasonable settlement of any
actions, suits, proceedings or claims), and the reasonable fees and expenses of
their counsel that may be incurred in advising with respect to and/or defending
any claim that may be made against the Advisor, to which the Advisor and/or the
Personnel or Senior Consultants may become subject or otherwise involved in any
capacity under any statute or common law or otherwise insofar as such Damages
arise out of or are based, directly or indirectly, upon the performance of
professional services rendered to the Indemnitor by the Advisor and the
Personnel hereunder or otherwise in connection with the matters referred to in
the agreement to which this is attached, provided, however, that this indemnity
shall not apply to the extent that a court of competent jurisdiction in a final
judgment that has become non-appealable shall determine that:

(i)     the Advisor or the Personnel or the Senior Consultants have been
negligent or dishonest or have committed any fraudulent act in the course of
such performance;

(ii)    the expenses, losses, claims, damages or liabilities, as to which
indemnification is claimed, were directly caused by the negligence, dishonesty
or fraud referred to in (i); or

(iii)   in the event that the Advisor breaches any material provision of this
agreement.

If for any reason (other than the occurrence of any of the events itemized in
(i) and (ii) above), the foregoing indemnification is unavailable to the Advisor
or insufficient to hold it harmless, then the Indemnitor shall contribute to the
amount paid or payable by the Advisor as a result of such expense, loss, claim,
damage or liability in such proportion as is appropriate to reflect not only the
relative benefits received by the Indemnitor on the one hand and the Advisor on
the other hand but also the relative fault of the Indemnitor and the Advisor, as
well as any relevant equitable considerations; provided that the Indemnitor
shall in any event contribute to the amount paid or payable by the Advisor as a
result of such expense, loss, claim, damage or liability any excess of such
amount over the amount of the fees received by the Advisor hereunder pursuant to
the agreement to which this is attached.

If a claim for Damages (a "Claim") is to be made by the Advisor or any of the
Personnel (an "Indemnified Party") against the Company, the Indemnified Party
shall give written notice (a "Claim Notice") to the Company as soon as
practicable after the Indemnified Party becomes aware of any fact, condition or
event which may give rise to Damages for which indemnification may be sought
hereunder. If any lawsuit or enforcement action is filed against any Indemnified
Party, written notice thereof shall be given to the Company as promptly as
practicable (and in any event within fifteen (15) calendar days after the
service of the citation or summons). The failure of any Indemnified Party to
give timely notice hereunder shall not affect rights to

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indemnification hereunder, except to the extent that the Company incurs actual
damage caused by such failure. After such notice, if the Company shall
acknowledge in writing to the Indemnified Party that the Company shall be
obligated under the terms of its indemnity hereunder in connection with such
lawsuit or action, then the Company shall be entitled, if it so elects, (i) to
take control of the defense and investigation of such lawsuit or action, (ii) to
employ and engage attorneys of its own choice to handle and defend the same, at
the Company's cost, risk and expense; PROVIDED, HOWEVER, that the party to be
indemnified may participate in the defense with counsel of its own choice and at
its own expense, and (iii) to compromise or settle such claim, which compromise
or settlement (A) shall be made only with the written consent of the Indemnified
Party, such consent not to be unreasonably withheld, and (B) shall not adversely
affect the Indemnified Party other than as a result of money damages or other
money payments which are fully indemnified by the Company. If the Company fails
to assume the defense of such claim within fifteen (15) calendar days after
receipt of the Claim Notice, the Indemnified Party against which such claim has
been asserted will (upon delivering written notice to such effect to the
Company) have the right to undertake, at the Company's cost and expense, the
defense, compromise or settlement of such claim on behalf of and for the account
and risk of the Company; provided, however, that the Indemnified Party shall not
settle any claim without the consent (which consent shall not be unreasonably
withheld) of the Company. In the event the Indemnified Party assumes the defense
of the claim, the Indemnified Party will keep the Company reasonably informed of
the progress of any such defense, compromise or settlement.

The indemnity and contribution obligations of the Indemnitor shall be in
addition to any liability which the Indemnitor may otherwise have, shall extend
upon the same terms and conditions to the Personnel of the Advisor and shall be
binding upon and inure to the benefit of any successors, assigns, heirs and
personal representatives of the Indemnitor, the Advisor and any of the Personnel
of the Advisor. The foregoing provisions shall survive the completion of
professional services rendered under the agreement to which this is attached or
any termination of the authorization given by the agreement to which this is
attached.