Here's what I'd do as a non-lawyer: 1. Write down the agreement you'd like to make in the plainest possible terms. Use simple English and structure the documen

Here's what I'd do as a non-lawyer: 1. Write down the agreement you'd like to make in the plainest possible terms. Use simple English and structure the document logically. Cover all the bases -- what you want to happen now, and in the future. Describe your theoretical idea as best you can. If you don't want each other to be able to compete in the future, write it down. But bear in mind that depending on where you are, you might not be able to force each other to agree to things like that. 2. I'm not a lawyer, but lawyers have told me to do the following things in agreements I've written: Describe which state's law covers the agreement in case you disagree about it later. Include the fact that the document is your entire agreement, and you don't have any other agreements on the subject outside of the document. Include something that says if any small part of the agreement becomes invalid for any reason (like the competition bit), the rest of the agreement is still valid. 3. Make two copies. Each of you sign and date both and keep one. 4. If you change your mind, make a new document that references your initial agreement (e.g., "this is an amendment to our agreement of Oct 8 2009") and spell out the changes in simple terms. That's probably the best you can do without spending any money on a lawyer. Think of it this way -- if you have a disagreement in the future you want something you can point to and say "this is what we agreed to, it's very clear". Don't try to fancy it up too much.