Okay, so Metal Gear on iPhone isn't a full sneak-off, but it probably wouldn't have worked anyway. Konami looks to be making a game that suits the touch screen and it looks very nice indeed.
As you can see, Metal Gear Solid Touch is a fixed-position shooter based on the Metal Gear Solid 4 storyline.
You tap the screen to shoot various enemies in a range of environments from the PS3 game, and duck into cover to avoid enemy fire. Could make a good pastime on the Tube.