Fair Use Information
Fair use is the safe harbor that allows for the use of protected materials under certain circumstances. There are four (4) conditions that should be considered when applying the priciples of fair use to any use of copyrighted work(s). A good discussion of the factors to consider in a fair use analysis is available at Georgia Harper's popular site at the University of Texas.
Stanford has a fair use site that is searchable and contains links to case law and other legal materials. Or try FindLaw.com.