Hey I created a script just for this! It automatically installs the media support for mp3, wma, wmv and dvd support! You can get it at:
Download the postinstall script. It will install all the appropriate codecs for mp3, wma and dvd needs. Let me know if ya need any help with it!
Edit: Hey and while your there, you can check out the mp3sort script! It can sort your mp3 collection by /Artist/Album or by /Artist!