AirPlay is a service that lets you stream video from an iPhone, iPod touch, or iPad to other supported devices, including a Mac or Apple TV. In other words, you can open a video on your phone and with the click of a button play it on your TV as long as you have a $99 Apple TV2 connected. Now there’s a plugin for the Totem video player that lets you stream AirPlay video to a Linux computer.
OMG Ubuntu has instructions for installing the plugin. Once you’re done, your Linux computer should show up on your iOS gadget’s list of AirPlay devices.
You can also use AirPlay to stream audio across your home network, letting you do things like stream your music collection from a MacBook to a computer in another room.