You won't believe this, there is a GTA5 trailer already... check it out. 
http://www.youtube.com/watch?v=eBGIQ7ZuuiU
You're right, I won't believe this because I'm smart enough not to. Even if and when Rockstar offers additional GTA games for this console generation, they won't be Grand Theft Auto V. Few gamers bother doing their homework, but Rockstar only increases the number with each new generation, meaning Grand Theft Auto V cannot and will not appear until the next generation of home consoles, which will start by 2011.
"What makes you so sure the next generation will start by 2011?" I hear someone asking? Again, knowing my gaming history. Console generations typically go five years. Nintendo in particular sticks to a rigid five-year plan. With the exception of the slightly longer gap between the NES/Famicom and the SNES/Super Famicom, they've stuck strictly to five years every time. SNES came in 1991, followed by N64 in 1996, followed by GCN in 2001, and then by Wii in 2006. There's a 100% chance of their next platform launching in 2011. As for Microsoft, the 360 launched in 2005, so five years would actually put them sooner, into 2010, but PS3 and 360 are both failing to sell at the rate of the PSX and PS2 before, so the current generation is moving more sluggishly, for which reason both Microsoft and Sony may wait a bit longer before shoving out their new hardware. Anyway, by 2011 at least one of the next-gen systems will be here, and the next Xbox may be here by 2011 as well. We won't see GTAV until at least then.
The history of the industry supports everything I just said.
