Copyright & Fair Use (Stanford University Libraries)
http://fairuse.stanford.edu/
The main page looks like an excellent starting point for finding information on copyright and fair use. When browsing the second level pages I found several broken links. The copyright on the main page is 2005; the copyright on the second level pages I looked at was 2004. I'm wondering if the site is still actively maintained. Still worth browsing but I'd like to know that I was getting the latest information.

Copyright and Fair Use in the Classroom, on the Internet, and the World Wide Web
http://umuc.edu/library/copy.shtml
From the University of Maryland University College, this discussion of copyright and fair use is geared specifically toward students and faculty. Has a section on the fair use Guidelines for Educational Multimedia. Includes a sample letter for requesting permission to use copyrighted material.

United States Copyright Office, The Library of Congress
http://www.copyright.gov/
Answers basic questions about copyright. The FAQs are interesting reading -- one of the questions is "How do I protect my sighting of Elvis"? School library staff will want to look at Circular 21: Reproduction of Copyrighted Works by Educators and Librarians.