I've been checking out these "augmented" apps for the iPhone, and they seem really sweet. I'm a big twitter-er, tweeter?... I use twitter a lot, and this app would be pretty cool.
http://www.youtube.com/watch?v=_Vbh7...eature=related
The concept of looking at things around you based on GPS and camera see through is really neat, wish WM would have something like this. It could be used for tons of stuff.
Another idea, an app that shows you nearest gas stations and their prices based on augmented reality. The possibilities are pretty endless for what this could be applied to.