I couldn't really care if MGS4 is exclusive or not (though I'd like to see some fanboy drama). I don't have a PS3 or 360 and I'm pretty neutral to Metal Gear as a series.
That said, people seem to keep wrapping themselves under this blanket of delusion that Kojima actually has some say on the matter. Konami decides what platform(s) MGS4 will go to, the most Kojima can do is whine and threaten not to cooperate on a port but he's not actually required in any way, they can just bitch slap him and port it.
People forget that Kojima didn't want MGS2 on Xbox and it happened anyway...
Claude tackles MGS4 exclusivity!
Some common excuses I hear:
Excuse #1: "But Kojima/Konami/Sony said it was exclusive!"
And? What are they supposed to say? It's not exclusive? If they haven't announced it for other consoles then by industry standards it's an exclusive. And they're going to continue to refer to it as an exclusive until the very day that they announce it to be multiplatform (if that day ever happens).
Excuse #2: "Xbox 360 can't handle Kojima's vision! MGS4 is not meant for it!"
Perhaps, but PS3 can't handle Konami's bills. This is perhaps the most expensive game Konami has ever make and they're putting it on a console that hasn't sold nearly as much as everyone had expected it to before launch. Judging by the fact that these multiplat rumors are being ignited by some Konami employees doesn't help the situation either.
Excuse #3: "Xbox 360 would explode if it tried to play MGS4/it needs 5 discs LOL/RROD LMAO!!1"
Yeah, keep telling yourself that.