Free online id3 tag editor
Add or edit id3 tags, image, album art, title, artist, and genre of audio mp3 files.
Batch edit id3 tags
At tagmp3.net you can batch edit id3 tags. You can basically upload multiple mp3 files at the same time, and then begin altering id3 tags of all your mp3 files. You can pick your custom album art to implant in the provided mp3 files, give different portrayals and produce final updated mp3 files.