They won't be released together, with the first coming in March of '08 and the other coming a bit later:
“The first 25 is for the first episodic content package that’s supposed to go out and that is in March of ’08. That’s why it moved into current because it’s in the next 12 months,” Take-Two CFO Lainie Goldstein explained. “The second 25 will be for the second episodic, the episode, and that will be later in fiscal ’08.”
You know you are in demand when a company pays you millions just to make a small bit of extra content for your console. Obviously this will help Take Two, who has been facing some financial woes the past year. All of this probably makes Jack Thompson very angry, with Take Two actively working to prevent him from messing with GTA IV's release.
Content exclusivity seems to me, however, to only benefit the console manufacturer. In the long run, it seems that it tries to further segregate gamers, forcing them into choosing one camp or the other. Two episodes for one game is one thing, but how much closer is it to a company bribing another to produce content only for them? Some companies will already only produce games for one console, as such is their choice. But bribing doesn't seem all that far off.
GTA IV is expected to be released on October 16th, for both the PS3 and the Xbox 360.