Help with agreement for "pro bono" work from someone

I`m hoping you can provide some advice concerning a start-up that I am working on.  I have begun work on a startup corporation, business plan, etc.  As part of this, I had a collegue sign an NDA and then revealed the business plan.  He is very interested in getting involved and offering his services designing marketing materials, web site, etc., without immediate compensation or equity.  His goal is that, if it moves ahead, he would have an opportunity to run a `branch` of the business in


Texas


(I live in MA).



 

We have loosely discussed that I would be interested in this type of plan, not offering equity, but offering some form of future franchise opportunity, or employment with profit sharing for his location.  It`s a little challenging, because it is too early to work out a very specific agreement about what he would get, when, etc.  And, he is not asking for these guarantees at this time.



 

My question is: What agreement should I have I place with him prior to allowing him to do this "pro bono" work?  I want to ensure that I own the work product, and especially that he is not automatically getting a right to some form of equity in the company.