Despite numerous sites taking the recent Gamespy press release to mean that Unreal Tournament 3 will include PC to PS3 cross platform play, this is still not necessarily the case. For those not in the know, Gamespy have recently partnered with Epic to offer all Unreal Engine 3 licensees the ability to connect to the Gamespy network and utilize its matchmaking and profile tools. This includes cross platform play between the PS3 and PC. While the partnership means that allowing cross-play would be easy, Mark Rein has stated to us that the decision to include it in Unreal Tournament 3 has yet to be made. As for other Unreal Engine 3 games, using these tools will be up to individual developers.
Mark was keen to emphasize that the Gamespy multiplayer tools are not a replacement for Games for Windows LIVE. It is simply another choice given to developers using the engine. We're sure that if anything changes regarding cross play for UT3 then an announcement will be made as appropriate. Until then, look forward to any and all Unreal Engine 3 games potentially having some excellent online play in the future.