Here are some links to selected important copyright documents including actual laws, acts and treaties.
Copyright Law of the U.S. - Title 17 (Text & PDF)
Copyright Registration Procedures - U.S. Copyright Office
U.S. Copyright Office, Information: Circulars and Fact Sheets (Text & PDF)
Digital Millennium Copyright Act - Summary (PDF)
Digital Millennium Copyright Act (PDF)
WIPO Copyright Treaty - 1996 (Text)