Supreme Court of the United States with decisions from 2000 to present available.
The Supreme Court Database (National Science Foundation) "contains over two hundred pieces of information about each case decided by the Court between the 1953 and 2008 terms. Examples include the identity of the court whose decision the Supreme Court reviewed, the parties to the suit, the legal provisions considered in the case, and the votes of the Justices.
FindLaw: US Supreme Court Decisions searchable database of the Supreme Court decisions since 1893 (U.S. Supreme Court Decisions: U.S. Reports 150-, 1893-). Browsable by year and U.S. Reports volume number, and searchable by citation, case title and full text. United States Reports: Cases Adjudged in the Supreme Court in print at Mount Holyoke, Call Number: KF 101 .A2, 4th floor Williston Library.
Federal Judiciary Center with biographies of federal judges since 1789, histories of individual courts, and landmark legislation.
Oyez Project: U.S. Supreme Court Media
Public Access to Court Electronic Records (PACER) an "electronic public access service that allows users to obtain case and docket information from federal appellate, district and bankruptcy courts, and the PACER Case Locator via the Internet." You'll need to create an account and the "use of web-based PACER systems will generate an $.08 per page charge. By Judicial Conference policy, if your usage does not exceed $10 in a quarter, fees for that quarter are waived, effectively making the service free for most users" (PACER FAQ)