As you all know the new iPhone 3G S has a build in compass. This allows creating Augmented Reality applications for the iPhone. Such applications are already available for Android Phones. They use the camera, compass and GPS of the mobile device to include additional (artificial) information on the camera view showing the current real situation.
I posted about an Augmented Reality application previously: http://joesonic.com/blog/2008/05/11/augmented-reality-and-mobile-gis-an-interesting-topic/
Following developer’s video shows an Augmented Reality browser running (in this case on an Android HTC G1):
