iOS: One of the biggest drawbacks of Apple’s new AirPlay streaming technology is the limitations of what video you can stream. Fortunately, with a jailbroken iOS device, you can install a hack that breaks down this barrier.
The hack is very simple. All you need a jailbroken iPhone, iPod touch, or iPad with iOS 4.2 (or greater) installed. From there, download the AirVideoEnabler app from Cydia. You may need to restart your iOS device for the hack to work, but then you can stream supported video (meaning most MPEG4/H.264 files) from any app that supports video out.
For a bonus AirPlay hack, check out MacStories for a tutorial on turning your iOS device into AirPlay speakers. (Thanks for the tip, Mike!)