Hi again L008,
As Blobby mentioned above, there are some available ID3-tagging scripts that depend on the presence of a commercial MP3 application (e.g., Frank Pope's 'MP3 Tagger' script uses SoundJam to do the actual tag updating). It might also be possible to perform a similar task with a free (and scriptable) MP3 application.
If you really do need a "stand-alone" ID3-tagging scripting addition (OSAX), unfortunately I don't know of any out there. You could try searching in all the usual suspects, such as
MacScripter's Scripting Additions library, if you haven't already done so.
Interestingly enough, there are some open-source APIs available for ID3-tagging (e.g., straight from the "horse's mouth" at ID3.org, there's the
'id3lib' C/C++ Library which apparently handles all ID3 versions). With a little luck, someone should be able to create a suitable OSAX by "wrapping" that MP3 API code in a standard OSAX shell (either from scratch, or by re-purposing the "OSAX wrapper" portion from one of the freeware OSAXen packages that include source code, such as Sean Hummel's
MacBinHex OSAX package). Any volunteers? ;-)
Regards,
--Paul