The Federal Court Locator (provided by the Villanova University School of Law) is intended to give net citizens a means to access information related to the federal judiciary, including slip opinions. This information can be viewed on-line or downloaded.
Official Site of the US Supreme Court. See the links for Opinions, Oral Arguments and Case Documents (dockets, orders and the Journal which are the official minutes of the court and go back to 1899)
Alternative Archives, Sites of Interest, and Information Sources
Recording of oral arguments can be found in the left-hand column of the page for each case. A case summary, case opinions and brief docket information are also available on this page.