I downloaded Light Bikes to my iPhone last night, I was surprised to find how fun it was in short blasts.
The 99 cent iGame has you maneuvering a light bike in a third-person perspective ala Tron against three computer-controlled light bikes. The graphics are fairly basic, but it works. You hold the iPhone sideways to play and to turn you tap either the left or right side of the screen. There's also a boost you can tap in the bottom center of the screen.