Uber has announced that its opening up an API so any app developer can integrate the car service into their app. While any app can pass a destination address to the Uber app, display pickup times, provide fare estimates, access trip history, most developers wont be able to call a car directly within their app. Uber says that because calling it immediately dispatches a real driver in the real world, we’re releasing it in a more controlled fashion, which means that only a few big-name apps (including, presumably, some of the previously-listed ones) will be able to do that.