A free app for iPhone and Android (BlackBerry available in the UK, Russia, and Israel), GetTaxi allows you to order a taxi or black car wherever you are, directly from your smartphone. GetTaxi uses state-of-the-art technology that allows you to order a car in seconds, tip the driver through the app and pay with a pre-stored credit card safely and securely. At the end of the ride, a receipt is delivered to your inbox. You can also rate your driver, view previous journeys and earn loyalty points towards free rides. Booking future rides is available in each continent and coming soon to New York.
For more see: http://www.gettaxi.com/