Crytek is currently working on Crysis 2 for all three platforms. The original Crysis was an exclusive for the PC. That being said, Crytek has already stated that Crysis 2 will be graphically superior on the PC.
"As long as the current console generation exists and as long as we keep pushing the PC as well, the more difficult it will be to really get the benefit of both," Cevat Yerli, founder, CEO, and President of Crytek, told the latest issue of Edge, according to CVG. "PC is easily a generation ahead right now. With 360 and PS3, we believe the quality of the games beyond Crysis 2 and other CryEngine developments will be pretty much limited to what their creative expressions is, what the content is. You won't be able to squeeze more juice from these rocks."
Developers have very low sales expectations for the PC, compared to consoles. It's a vicious cycle: the PC market doesn't give the same revenue as the console market, so companies don't spend much on the PC version of a game. This is certainly true for games like Unreal Tournament 3: it would have been much better had it been released as a PC exclusive.