NPR has learned that Supreme Court Justice David Souter is planning to retire at the end of the court's current term.
The court has completed hearing oral arguments for the year and will be issuing rulings and opinions until the end of June.
Souter is expected to remain on the bench until a successor has been chosen and confirmed, which may or may not be accomplished before the court reconvenes in October.
At 69, Souter is nowhere near the oldest member of the court, but he has made clear to friends for some time now that he wanted to leave Washington, a city he has never liked, and to return to his native New Hampshire.
Now, according to reliable sources he has decided to take the plunge and has informed the White House of his decision.
Souter's retirement would give President Obama his first appointment to the high court, and most observers expect that he will appoint a woman.
Update: Sam Stein at HuffPo also has five likely picks.
Update II: And more here, including photographs of the several potentials. The buzz I am hearing the most surrounds two names: Sotomayor and Sunstein.