mBox is a free GPL'ed program intended to help you with organizing your music files.
It's known to run on *BSD, Linux and Solaris. It should also work on Mac OS X, however it's not proven, so any feedback by Mac users would be greatly appreciated.
The most important features are:
- ability to reencode mp3/ogg/wma to mp3/ogg
- contains utility 'convertor' which converts whole directories to desired format. Bitrate, etc. is automatically adjusted depending on settings and source audio. See user's guide for further information
- supports reading/writing tags in MP3 ID3v1 and ID3v2, Ogg Vorbis
- supports reading WMA tags
- supports FreeDB, treates encoded files as if it was CD, so you can simply select your files and - if found in database - write tags to them. Nifty, isn't it? =)
- supports auto tagging - reads tag information from filename
- supports batch tags editing
- supports batch files renaming (can use tags)
- supports directory renaming (can use tags)