Here's how it works. "Select a destination from our London map or use your GPS to locate an image near you. Hold your camera up to the present day street scene and see the same London location appear on your screen, offering you a window through time. If the image is flipped, just walk around it to see it from the correct viewpoint. Want to know more about what you’re seeing? Simply tap the info button for historical facts.
Once you’ve got the hang of it, use Streetmuseum to create your own trails around London. At home, on the way to work or enjoying a trip to the capital – whatever you're doing, Streetmuseum offers you a different outlook on London."
I'm not sure how many Tube stations are pictured in the app - but for those of you with iPhones, it's another nice app to add to the London Undergroundrelated ones.