Windows users can now play some games online against X-Box 360 gamers via the compatible X-Box / Windows Live network. Currently supported games include Dirt 2, Street-Fighter 4 and Bioshock 2.

Unlike the X-Box 360, there's no subscription fee to play online, but you can't access all the features of the X-Box Live network like film downloads and avatars.

Actually, none of these games support cross-platform gaming between X-box 360 and PC, but there a few others that do.