Thanks very much for the Winamp/autotag suggestion. It works well!
As you mentioned it edits FLAC files. Is there a way of getting it to update AIFF files directly without me having to do the conversion to FLAC?
(note: winamp will read the aiff files, it just wont update them with the metadata. I know how to convert aiff to flac and back again, but I would just as soon avoid this step if possible. I also know there is a debate about whether all lossless formats are sonically the same or not.)