Uber is a car service with a kick-ass iOS app. Launch the app and a map appears showing all the “black cars” in your area, with the time until the closest one can get to your location. Tap a button, the car is instantly dispatched. When the driver gets close, they’ll call and/or text you to let you know the car is near. You rank the drivers (1-5 stars) and they rank you, too. Terrific experience, just a bit more expensive than a cab, but much more convenient and incredibly reliable.
The fact that they are raising so much money is a sign of both the maturation of this space, and of its competitive nature.