After Rockstar's announcement confirming GTA IV for PC, some speculation has arisen about how the game will function online. Given that the game is being released with a Windows LIVE logo, some are speculating that not only will you be able to play it online with other PC users, but perhaps console players as well.
Cross-platform multiplayer gaming is an interesting idea, and with the advent of modern consoles supporting Internet connections it's clearly possible. There are a lot of obstacles, however. For one, console and PC development are rarely done side by side, and keeping the games patched simultaneously could be a development nightmare. On top of that, more simplistic issues like the controls for a console not matching the PC version could inspire some to say that certain players have advantages over the other. Not to mention that people cheating in PC games online is a big issue, whereas it's rarely heard of in multiplayer consoles.
I don't see it as happening – but I hope it will, since it would tie two large pools of gamers together.