United States Supreme Court website provides information on Supreme Court cases, including dockets, briefs, transcripts, and opinions. In addition, it provides information on the Supreme Court Justices.
SCOTUSblog includes United States Supreme Court case information from the recent terms, such as oral argument transcripts, briefs, and opinions when available.
OpenJurist includes Supreme Court opinions beginning from its first term in 1790.
Making of Modern Law contains records and briefs from over 15,000 Supreme Court cases from 1832 to 1978, most without a full opinion.
FindLaw includes merits and some amicus briefs, along with dockets and orders from the 1999-2007 terms.
If a public interest organization is involved with a case or has submitted a filing or is following the case, try the organization's website. For example, ACLU's homepage.
The Oyez Project is a database on major constitutional cases heard by the United States Supreme Court, with multimedia resources including ditigal audio of oral arguments from 1955 to the present.
Transcripts of earlier Supreme Court cases are available on Lexis Advance (1978 - present) and Westlaw (1990 - present).
For immediate access to transcripts, The Supreme Court's official reporting service posts the latest argument transcripts on the same day as the oral argument. The Court's website contains transcripts of oral arguments dating back to 2000 in PDF format.