Acrossair Augmented Reality Browser
Acrossair is the Swiss Army knife of augmented reality. When you hold your phone horizontally, it shows your location on a map, and you can select the layer you'd like to see. You can view cinemas, hotels, and many other amenities, check out geotagged Wikipedia entries, or see local tweets--you can even pin a location to find your car later. Once you've chosen a layer, simply hold your phone upright, and the full-screen camera viewfinder appears with overlaid information that pops up in see-through balloons as you move around.