Dallas: Do you belong to a performing rights organization? If so, that's one place to look for info. Also the SCL (Society of Composers & Lyricists) is a group for film composers. You might consider joining to gain access to such info. I think all you need to be a full member is one film credit (this includes film in the works), but you can find out for yourself at www.thescl.com.
On a short, it really isn't as complicated as you might think. What you should definitely do immediately is send the director/prod a "deal memo". A deal memo is essentially a short format agreement which cements the main details of the long format and more formal agreement to follow. Basically, the DM will list out how much you are to be paid, when you are to be paid, who owns the music, and when the project is due. This will do a couple of things for you: It will protect you immediately as you work through your arrangement with the production company, but it will also buy you some time to get a more formal agreement in place, i.e. a composing contract.
Here in Hollywood, a DM followed by a contract is standard practice and used every day. If you'd want to message me offline, I'd be more than happy to forward you what I use so that you can see where to get started.