This applet will assist with swapping, copying, and appending data between two user-chosen tags in selected tracks or tracks in the selected playlist:
Swap - swap data between tags, ex: ARTIST<->COMPOSER
Copy - copy data from one to another tag, ex: ARTIST->
Append - append data from one tag to the end of another, ex: ARTIST->COMPOSER - ARTIST
Prepend - prepend data from one tag to the beginning of another, ex: ARTIST->ARTIST - COMPOSER
The latter three actions also provide an option to delete the info from the first tag after the copy. Read Me explains all.
For OS X 10.8 or later only. This update is free for registered users of v4.x.
Select the Action to perform between the two chosen tags in each selected track.
Create text file listing tracks common to and exclusive to two playlists
Remove iTunes tracks disassociated from files
Make selected tracks NOT bookmarkable
Export artwork of selected tracks to parent or specified folder
Exports and then re-imports selected tracks' artwork
Create a Ringtone track from a selected track