Our colleagues from G4TV.com revealed the british cover of the GTA IV PC version.
Besides of presenting the layout, it brings more information: On the one hand it shows the "Games for Windows" -bar, which means that the game will support 32- and 64-Bit.
On the other hand there is a "live" sign on the right side of the bar. This would mean that the game has to maintain standards like including the Xbox 360 achievements, Xbox 360 controller support and it must run under Windows XP and Windows Vista.
Furthermore, it could be possible that Xbox 360 and PC players get a combined Multiplayer -Mode.
Up to now RockstarGames gave no official commentary of these rumors.