Here are some links to selected important copyright documents including actual laws, acts and treaties.
Copyright Law of the U.S. (Title 17 - text – downloadable)
Copyright Law of the U.S. (text)
Copyright Registration Procedures
U.S. Copyright Office, Information: Circulars and Fact Sheets (pdf & text)
Digital Millennium Copyright Act - Summary (pdf)
Digital Millennium Copyright Act (pdf & text)
WIPO Copyright Treaty - 1996 (text)
TEACH Act (text)
Berne Convention (as revised – Paris Text - 1971)