On Friday, Justice Souter announced his intention to retire from the Court at the end of its current term. 

For a crash course in how the nomination process works, read the Congressional Research Service's report Supreme Court Appointment Process: Roles of the President, Judiciary Committee, and Senate (last updated 3/20/08).

The Library recently updated the Supreme Court Nominations Research Guide.  It includes links to materials about the nomination process and the text of previous nomination and confirmation proceedings.