Mac OS X: If you lack for an infrared remote or Boxee remote app, or just like to keep your laptop near your big screen, one intrepid coder has whipped up a remote control widget for the social media centre.
The widget uses the remote web interface of Boxee to control the media centre, which also happens to be the same API that any XBMC-based media centre uses—so be sure to let us know if XBMC proper or Plex works with this widget. Otherwise, it's just a helpful little widget that puts directional controls, typing input, and volume buttons on your desktop. You might need to pin down your Boxee center's host name once, but after that, the widget can find it automatically if you're connected to the same Wi-Fi network.
Boxee Remote 1.0 is a free download for Mac OS X systems only.