Main features:
Batch Tag Editing Write ID3v1.1, ID3v2.3, ID3v2.4, MP4, WMA, APEv2 Tags and Vorbis Comments to multiple files at once.
Support for Cover Art Download and add album covers to your files and make your library even more shiny.
Import from Amazon, discogs, freedb, MusicBrainz Save typing and import tags from online databases like Amazon, discogs, freedb, MusicBrainz, and more.
Replace characters or words Replace strings in tags and filenames (with support for Regular Expressions).
Create Playlists automatically Create and manage playlists automatically while editing.
Rename files from tags Rename files based on the tag information and import tags from filenames.
Export to HTML, RTF, CSV Generate nice reports and lists of your collection based on user-defined templates.
Full Unicode Support User-interface and tagging are fully Unicode compliant.
Besides these main features Mp3tag offers a variety of other functions and features ranging ranging from batch export of embedded album covers, over support for iTunes-specific tags like media type or TV Show settings, to combining multiple actions into groups that can be applied with a single mouse click.