Okay, acrossair's New York Nearest Subway application is awaiting approval from Apple and is only for Apple iPhone 3GS users, but this video showing what it does is still pretty cool: It creates an "augmented reality" of your surroundings and transposes various subway routes into the phone camera's field of vision. Here's the acrossair's:
When you load the app, holding it flat, all 33 lines of the New York Subway are displayed in coloured arrows. By tilting the phone upwards, you will see the nearest stations: what direction they are in relation to your location, how many miles away they are and what lines they are on. If you continue to tilt the phone upwards, you will see stations further away, as stacked icons. Only available to Apple iPhone 3GS users.
Imagine if there was cellphone service in the subways and the acrossair people worked on some sort of partnership with the Exit Strategy folks...