I was looking around for a way to play .mov files on the 360 and I found something much much better- the TVersity audio and video server. It supports pretty much any format as long as you have the codec for it. They auto-install pretty much all of the codecs you need, so it isn't a problem. It supports many many devices, even the Nintendo Wii! It can be accessed through a web browser or through network discovery on the Xbox 360 and the PS3. It will also translate the video or audio formats on the fly, so if you device doesn't support something, it will find something it does. This really is an amazing piece of software.
This one tip will help you sleep better tonight
A few seconds are all you need to get a better night's rest.