Augmented reality is going to be the most helpful location-based informational tool of the future. Point your phones camera at anything and up pops information regarding that object or area. The applications for this technology are limitless. From games, history, tours, orgs and government info, our world will become more transparent. We'll peer into the world around us with new eyes gathering new information.
Check out this NPR article for a small taste of what is possible.
Here's a cool game called Firefighter 360. As games evolve, look forward to running around your surroundings shooting virtual enemies - instead of imagining the whole thing in your head like when you were a kid!
The Layar browser is the forefather of it all.