Adapted from Chess.com:

The winner of the 2009 World Cup will gain entry to the 2010 8-player Candidates tournament that will decide a challenger for the winner of the Anand v Topalov WCC title match in April next year. The next Championship match will be in 2011.

The other players in the candidates tournament will be:

The 1st (Aronian) and 2nd (currently Radjabov) finishers in the Grand Prix
The loser of the WCC match between Anand and Topalov
The 2 highest rated players not otherwise qualified (currently Carlsen and Kramnik)
The loser of the 2009 challenger match (Kamsky)
A wild-card nominated by the organisers (must be 2700 Elo+).

Shaping up to be a pretty strong Candidates' Matches !

Bob