Program: Tag Scanner
License: Freeware
Description: TagScanner is a multifunction program for organizing and managing your music collection. It can edit tags of mostly state-of-the-art audio formats, rename files based on the tag information, generate tag information from filenames, and perform any transformations of the text from tags and filenames. Also you may get album info via online databases like freedb or Amazon. Supports ID3v1, ID3v2, Vorbis comments, APEv2, WindowsMedia and MP4(iTunes) tags. Powerful TAG editor with batch functions and special features. Playlist maker with ability to export playlists to HTML or Excel. Easy-to-use interface. Built-in player.
Website: http://www.xdlab.ru/en/
Other: Has a portable zip on the site for download. Shouldn't be too hard for a dev to create a PAF Live installer
Mp3 Tag Tools (Open Source + Portable)
http://massid3lib.sourceforge.net/
Looks good but TagScanner is more robust and is still actively developed. Massif3lib's last release was in 2003. I recommend you have a look at TagScanner and let us know what you think.
PortableApps.com Advocate
There is TagScanner Portable on author website. What we need is just a launcher