NBA free agents are players whose contracts have run out. Unrestricted NBA free agents can sign with any team in the league who offers them a valid contract. Restricted NBA free agents can do so as well, but if they do so with a new team, the previous team has the right to match the contract and keep the player.
Normally, NBA free agent negotiations begin in early July, with actual free agent signings beginning a week or two later, but due to the awful, evil NBA lockout, which began July 1, negotiations and signings are suspended indefinitely.
Eventually, when the lockout ends, NBA free agents will get to negotiate with teams, per usual.
Here is an unofficial list of 2011 NBA free agents, per Fox Sports Ohio, as of July 25, 2011. Now (Noember 26, 2011) that the NBA lockout will soon end, we'll update it soon, and always rank the best overall free agents in the next few days.
Free agent notes: (R - restricted; P - player option)
Atlanta Hawks: Jason Collins, Jamal Crawford, Josh Powell, Etan Thomas, Damien Wilkins
Boston Celtics: Carlos Arroyo, Glen Davis, Jeff Green (R), Troy Murphy, Aleksandar Pavlovic, Von Wafer, Delonte West
Charlotte Bobcats: Kwame Brown, Dante Cunningham (R), Dominic McGuire, Joel Przybilla, Garrett Temple
Chicago Bulls: Rasual Butler, Brian Scalabrine, Kurt Thomas
Cleveland Cavaliers: Anthony Parker
Denver Nuggets: Arron Afflalo (R), Wilson Chandler (R), Melvin Ely, Gary Forbes (R), Kenyon Martin, Nenê (P), JR Smith