iPhone-controlled LEGO robot
If you've got two iPhones and a LEGO Mindstorms kit, you too can build your very own iPhone-controlled LEGO rover. Just check out what they've done over at BattleBricks; they provide the LEGO model and source code for you to join in the fun. Basically, one iPhone generates color patterns on the other iPhone's screen that the NXT brick can recognize and respond to.
Now imagine what they'll be able to do with the 3G iPhone's GPS receiver...
Via Ars Technica