Hey, it worked for the Wii, so why not the iPhone? CTA Digital is now selling a rubber steering wheel to stick your iPhone into to make driving games more "realistic."
I'm sure it does improve the control, but how do you touch the screen if you need to brake or hit a nitro booster? And what if you get a phone call while playing, do you hold the wheel to your head? But hey, if you're super into driving games on your iPhone maybe this is worth the scratch to you.