Foray into augmented reality with Layar

Just got hold of 'Layar', an augmented reality app for iPhone. As well as the incredible possibilities it has for locating information, local services and businesses, and for social connectivity I can imagine using it to make drawings. It works by pointing the phone's camera at an environment and allowing you to call up information about the area, which is represented in the form of graphics layered over the top of the real environment on the screen. It provides apps within the app, providing another layer of possibility for third party developers. It has me thinking that you could add drawings as information within an environment, which could be a city or maybe just a gallery space. Images can be layered on top of the actual environment - in the way that the Terminator does when he looks around the room (thanks for that,Simon Cox, Click On, BBC R4).