you might be out of luck if you made the introduction already without having anything in writing. you can create a commission agreement based as a percentage of total project value and treat it a piece of real estate or just set a fixed amount that you see fair for brining the parties together. either party can be responsible for paying your fee depending on what they're bringing to the table, i.e. one party is a land owner and the other deep pocket developer, in which case the developer might be paying you commission. in this case there are really no set rules as every transaction is different.
good luck and hope this helped
Apr 8, 2010