The Wikipedia entry has grown to be quite thorough in its discussion, and is well worth a look. The External Links and Sources section at the end is quite a nice list for studying fair use. The article is U.S. centric, which is appropriate since most of the fair use law and discussion is taking place in the U.S.
This podcast is 14 mintues of conversation between Mary Minnow, of the Stanford copyright web site , and Richard Stimm, of Nolo. It's a brief overview of fair use and a good introductory discussion.
Well, it's not *everything* the Copyright Office thinks about Fair Use, however it is an absorbing discussion about ripping DVDs and DRM.
These guidelines from North Carolina give a sense of what is out there and being used for multimedia in schools.
Fair Use is getting a lot of deserved nit-picking these days and Villanova Professor Michael Carroll's points are interesting contributions. Published as Villanova Law/Public Policy Research Paper No. 2006-21 and
North Carolina Law Review, Vol. 85, 2007, the paper is also retrievable on the Social Science Research Network (SSRN).