On topic:
http://ps3.thegamereviews.com/story-342-Rumor-Killer-No-MGS4-on-360-says-Konami.html
This rumor keeps popping up because XBox360 owners really want MGS4. The majority of them are more hardcore gamers than a lot of PS3 owners. I believe a great number of Xbox360 owners will eventually get a PS3 to play this game.
Edit: Sorry, didn't know there is another thread showing the link above.
It (PS3's market share) might hit 30%, but definently not more. ~ Neo
Flaming (Calling another user (any user) a fanboy is flaming.) ~ Machina-AX