You seriously think Konami would fire Kojima? Seriously without Metal Gear and his work, the company would be a tiny fraction of what it is now. They would rely on Pro Evolution...
I think it will be a 1 year timed exclusive. 6 months or so after it comes out on the PS3, they announce a 360 version and that comes out 6 months later. This is if the sales on the PS3 aren't as high as they hoped.
Thanks to Blacksaber for the sig!