While preparing to launch Grand Theft Auto V, Rockstar Games announced that they will simultaneously release a MMO-ish online version of the game that will allow up to 16 players to participate in missions together. You can earn virtual money and buy things like clothes, guns, rides and even apartments. You and your friends can plan and execute heists and other crimes, just like in real life
The best news is that Grand Theft Auto Online will come free with every purchase of Grand Theft Auto V. But watch out for in-game enticements to pay real money for stuff.
See their commercial: