I have been thinking about motion in mobile gaming for a while.  I guess Sony is looking into that as well:

http://www.engadget.com/2008/06/17/sony-ericsson-makes-good-on-motion-gaming-f305-and-s302-snapshot/

My boss just got an iPhone (I am the only one in my group that is still on Windows Mobile).  He showed me this motion sensing dice roller:

http://gizmodo.com/5023627/iphone-dice-game-simulates-real-dice-rolling-using-sensors-and-physics

WOW!