Good news for everyone waiting for the next GTA: Rockstar Games have officially announced GTA V. A first trailer can be seen on 02.11.11, so stay tuned!
Rumours says, that GTA V will be set in L.A. It is also said, that there will be multiple characters to play. (source: Grand Theft Auto V Will Be Set in Los Angeles, May Star Multiple Characters)
Update:
Here is the official trailer.
Enjoy!