Information about an audio file can be stored as part of the audio file itself (at least in OGG or MP3 format). This can include track titles, artists, album titles, genre, and more. You can view the information using the vorbiscomment command:
$ vorbiscomment -l track05.ogg title=Mother artist=Roger Waters album=In The Flesh - Live tracknumber=5 genre=Rock
Other useful tools for editting the audio information includes the terminal-based orpheus (not currently packaged for Debian as of 11 March 2004).