AirView lets you stream video between iOS devices
The AirView app from developer Clément Vasseur enables video streaming between any iOS devices (iPhone, iPod Touch or iPad) running iOS 4.2 on the same local network, or from iTunes.
It’s free and worked flawlessly for us. It would be great if this could stream audio to another iOS device, but all in all, it’s perfect at what it does.
AirPlay is not available any more at AppStore