there is a great app called ialertu for mac that basically when you "arm" it, if you touch or move the computer it starts an alarm (macbook pro)
and the screen freezes, it is an amazing app!
can someone do something similar for the iPhone???
Don't really see how this can be implamented. However, using the almost-GPS system in the Iphone and with a system similar to a heartbeat system. It should be possible to locate a Iphone to within less than a mile.