Argument Transcripts of cases presented before the Supreme Court can be found here, and will be permanently archived on this site, although at present they are available retrospectively only back to October of 2000.
The OYEZ Project at Northwestern University, is a multimedia database containing U.S. Supreme Court oral arguments, case summaries, and much more. The selection of cases is limited to those for which multimedia is available and to essentially constitutional law cases, generally dating from the 1950's.
U.S. Appellate and District Courts
U.S. Federal Courts Finder - clickable US map showing locations of the US Circuit Courts (Court of Appeals).
Lexis-Nexis Academic Universe - Legal Research contains virtually ALL legal opinions from the Federal court system, including the Supreme Court, Court of Appeals, and District Courts, BUT IS AVAILABLE ONLY TO UNCG AFFILIATES!