For an excellent explanation of the law and your rights, check The
Writer's Legal Guide: An Authors Guild Desk Reference (Allworth Press, 2002) out of your library.
You may also look for information from the
Authors Guild, the
National Writers Union (US), or a local chapter of
Volunteer Lawyers for the Arts.
In addition,
The Practical Writer (Penguin, 2004), which was edited by the staff of
Poets & Writers Magazine, includes an excellent essay about negotiating your first book contract that can help you understand the business of granting rights to publishers.
Once again, however, when dealing with a small or independent press, be prepared to do things a bit differently. A good small press publisher, realizing you are a first-time author, will walk you through the process. I have, anyway, in the past with authors unfamiliar with the process.