MP3 files have had tag properties forever, and it actually seems somewhat odd that they're not accessible in Windows Explorer, as part of the file properties pane. AudioShell fixes that, by exposing the audio file's id3 tags right within Windows Explorer where they can be viewed and updated.

AudioShell supports editing file tags individually, or doing groups of files all at once. It adds a verbose tooltip window when mousing over audio files, and adds the ability to choose specific id3 tags to add as columns in Windows Explorer, so you can easily sort by them, or manipulate your files as needed.

AudioShell is free, and supports the following file formats:

• mp3 (all ID3 tag versions)
• wma, asf and wmv (including DRM protected files)
• Apple iTunes and iPod aac (m4a, m4b and m4p) and mp4 files
• ogg, flac (vorbis comment tags)
• mpc, mp+ (APE/APEv2 tags)
• monkey's audio (APE/APEv2 tags)
• wav pack (APE/APEv2 tags)
• optim frog (APE/APEv2 tags)
• wav (ID3v2 tag in 'tag ' RIFF chunk)

[via Windows Fanatics]