Sister site Xbox 360 Fanboy and Xboxic have been following the story. Turns out that Che Chou, who is identified as an ex-1UP staffer says, "It's simply a rumor that Konami higher-ups are pressuring Kojima Productions to consider making MGS4 a multiplatform game because production costs on the game are unsurprisingly high and only getting higher ... Whatever the case, I highly doubt it's going to happen so quit building yourself a disappointing kiloton bomb."
We've contacted Konami's PR department and they said, "Metal Gear 4 [sic] is a PS3 title." Doesn't seem like EGM made a deal to get some exclusive info, but instead took a rumor, slapped a question mark on it, and hoped to build hype and sell magazines. Hey, we don't fault them, check out our headline above! Maybe the info is worth the price of the magazine? The rest of the cover info is snore inducing and has already been covered to death. The Halo 3 info was already leaked, but EGM says no, no, wait -- we have more info not leaked, please buy us.
It's a brave new world and the ball is certainly in the publisher's court. Konami very well may be having cocktails with Ubisoft (Assassin's Creed) and getting whispers that exclusivity isn't as important as making money. Now we'll go back to building our kiloton bomb.
[Update: Added Konami PR quote]