The Supremes

The OYEZ Project provides access to more than 2000 hours of Supreme Court audio. All audio in the Court recorded since 1995 is included in the project. Before 1995, the audio collection is selective. The sites aim is to create a complete and authoritative archive of Supreme Court audio covering the entire span from October 1955 through the most recent release.

SCOTUSblog - of course, there's a blog, which provides discussion of recent developments in US Supreme Court jurisprudence.