Writing Your Own NDA?

Trak writes "I am not a lawyer, nor can I afford one. I have a cool idea that I think could make some money, and I'd like to pitch this idea to a couple CEO/entrepreneur buddies of mine for a joint venture (they provide the money, I already have the technology). Yes, they are friends, but they are also businessmen and I wouldn't put it past them to take my idea and run with it. How can I protect myself and my idea, such as drafting an NDA and having them sign it before hearing my idea? What would I need to include in such a document?" I'm sure many of us have been in this position before and didn't know what to do. For those who have written one, if you would please share some information and insight on what you did and why?