This one works with PC (Windows 2000, XP, Vista, and no doubt Windows 7), PS2 and PS3. With it you get a wheel and a gearstick (which may suit US gamers better, it being on the right hand side of the wheel) on one console with suction pads for stability, and a set of two pedals. You can get it on Amazon for £29.99 here.
In terms of realism, of course, there is no clutch for gear changes and you would have to pay more for a model that has three pedals, but this is not the only issue. Had the wheel been made specifically for PC it may have been better, but Amazon reviews have said that there are calibration problems and a sizeable dead zone (although this is more obvious on the PS3). For Gran Turismo, though, it apparently works excellently, and for its price it is would be a good purchase to go with any driving game.