Hudson Soft recently released AR Monster on the AppStore, a new Augmented Reality game for the iPhone 3GS (3.1.2 or later). It's good to see new apps taking advantage of Augmented Reality, hopefully we'll see the envelope pushed further in it's development. In the meantime, AR Monster is currently available for Free so you can have a play around with it at no expense and little fuss.
AR Monster is a role-playing game that integrates augmented reality technology. Players can discover more than 600 monsters with their iPhone's camera and battle in an augmented reality world. Players will discover more monsters by pointing their camera's view finder in different directions and by moving to new locations. AR Monster uses the iPhone's GPS system to make completely different monsters appear in different geographic locations!
AR Monster also uses OpenFeint for its global leaderboards and achievements and connects its game players to the mobile social network's 26 million players.