The first downloadable Grand Theft Auto IV content is due in the first quarter of 2009, according to an investor conference call with Take-Two CEO Ben Feder. Quarter 1 is between November 1, 2008, and January 31, 2009.
Apparently, this is specifically for the Xbox 360 version. No word on the PlayStation 3's DLC.
There are no other details right now. We don't know what the content is going to be, what it will cost, etc, but you can bet when we hear anything, we'll let you guys know.