Wow… this iPhone app from acrossair is just too cool (via The iPhone FAQ).
Instead of a static map, Nearest Tube displays subway information in real-time, overlaid in 3D on top of live video of the user's surroundings. Holding the iPhone 3GS horizontal will show arrows pointing to different train stops, and tilting the device upwards will overlay signs in the direction of different stops. These signs look like a heads-up-display, and give more information about how far away the station is and what lines connect there.
You really need to see this thing in action:
If you ask me, that’s much cooler than that app that’s been getting a lot of press about where to stand on the subway. (That’s something that is most useful during rush hour and most New Yorkers have figured that out already!).