http://www.mp3tag.de is a pretty nice bulk id3 tag editing application for windows, obviously requires you to make a public share mapping onto your slug music folder.
or im also using the id3 app on the debianslug nslu2 to do tagging
my only issue is im not convinced that the mt-daapd database is picking up new tags in mp3s. not sure if you need to force some kind of rescan, or its supposed to just ‘know’ next time its started! .. i presume the solution isnt to rm the songs.db file anymore, as isnt it holding things like playlist data as well as the songs themselves??