Thomas Pleasance's AirPlay for Windows Media Center addin seems to already be one of the smoother combinations we've seen and it's still in beta. Unsurprisingly, it does what the name says, so after installing Apple's Bonjour service and the free client on your Media Center PC you should be able to stream video or pictures to it (there's no support for music yet) from an iPad or iPhone with a simple click.
You can download the addin free from the link below. Bonjour comes with any Apple downloads for Windows. ie (iTunes, QuickTime, Safari).
Read More [via Engadget]