I run an IT consulting and staffing service. We have a few private and
govt. clients
nationwide, it has been a one man show so far. I have our first
pitch with top brass of a multi-billion dollar firm. I requested some
colleagues (subject matter experts) to help me with the presentation.
They want to find out
what their gain would be if things come through. I have not really
given much thought. As much as I want to be fair, I don't feel that I
should be throwing away partnership for the company that I have built
in years, and also that I have been the sole marketing/networking
individual for this contact.
Any thoughts?

I would recommend that you do not give away shares of your company
unless the likelihood of a successful venture is heavily dependent on
your colleagues.  Perhaps you can discuss a fixed payment that is
dependent on the outcoming of the meeting.

Ask this guy:

http://www.forbes.com/columnists/2005/05/13/cx_gk_0513artofthestart.html

I've written him before. He's incredibly responsive.