This free iOS application allows you to send or received UART messages between your iOS device and the nRF8001 (select UART on the home page), or toggle pins from the iOS UI setting them to input, output or as PWM (select Pin I/O discussed in the next page)
The echoDemo example sketch allows you to send and receive simple messages using Serial-esque style commands, and the data will be displayed on both BlueFruit on the iOS device and the Serial Monitor on the Uno.
After programming the Uno with the sketch, you can open up the Serial Monitor (make sure it's set to 9600 baud!), and then open up the BlueFruit application on your iOS device and select UART on the home screen. It should connect!
Now, any data that you enter on the iOS device or the Uno will be transmitted to the other device as long as the connection is open: