As ESPN's Adam Schefter reported earlier this week, Nnamdi Asomugha is now a free agent due to his contract being void. Nnamdi's contract contained a clause that stated that if he did not play in a greater amount of games in 2010 than he did in the 2009 season, then he would become a free agent.
He did not meet this as he missed games in 2010 because of an ankle injury. There is another clause that states if he does become a free agent because of the playing time clause, then the Raiders can not place a franchise tag on him.
Asomugha will easily be the most sought after free agent this offseason. Known for being a "shutdown corner" and one of the best players on the defensive side of the ball, he will also be paid like it.
Teams will not be able to sign Asomugha for cheap as he is used to lucrative contracts and will command so. He might be willing to take less money for the chance to win, but this is purely speculation on my part.