The NeoGAF moderator that confirmed the rumors surrounding the GTAIV bundle has just posted another confirmation that, the bundle is 150% Exclusive to the PS3 and that, there are currently no plans for a 360 bundle.
He wrote: "I literally heard this morning, again, that the "official" bundle will not be available on launch day (more like weeks later). So I'd still say it isn't confirmed, but still possible.
One thing is for sure... the bundle itself is 150% confirmed, along with it being exclusive to the PS3. Absolutely 0 information about a U.S. bundle either way."