Everyone else is reporting this today so I might as well throw it up too. Last week, Konami released the cryptic teaser "i + ! = (!)", in green lettering. Many pundits believed that this was a secret message that indicated that Metal Gear Solid 4 would be heading to the Xbox 360, given the consoles' trademark colour and power button. Unfortunately, Xbox fanboys will have to wait a little while longer before Solid Snake makes an appearance on their system. Konami has revealed that the next Metal Gear title will be on the iPhone and iPod Touch. It is said to be a watered down version of MGS4 with touch controls but it's more likely a spin-off of that game. The new title will be known as "Metal Gear Solid Touch". Release dates and prices have not been confirmed.

MGS4 was not released on the Xbox for a variety of reasons. Primarily due to Konami's past relationship with Sony on the series and that DVD-9 discs used for the 360 were not big enough for the game. MGS4 would require at least 4 DVDs for the 360. An unreasonable number for many console gamers.

Source: Joystiq