The iPhone doesn't seem to be the ideal platform for a First-Person Shooter - graphically it is more than up to the job, but the controls would seem to be a problem.

Taking a tip from the port of Quake 3 to the Jailbroken iPhone/Touch, Source IT software are working on a new game, Zombie Mansion, that uses the accelerometer to control movement, with screen taps firing weapons.

According to Source IT the game will be finished "When it's ready", which bodes well we hope.

Zombie Mansion [Source IT]