How to Use your iPhone or iPod touch as a 2nd monitor
If you're looking to expand your viewing space, and haven an iPhone, iPad, or iPod touch, you can follow this how-to and learn how to do it. You'll need to get an app from the Apple App Store called SideMonitor. With this little app, you'll be able to connect your Mac or PC to your hand held device to get a bit more viewing room. It seems like you can never have enough viewing space, so don't poo poo the idea of hooking up some smaller devices.