This script will apply user-entered text to the "Category" tag of each of the selected tracks. iTunes 5 or better.
(Note: In order to launch this PowerPC-era script on an Intel machine, it must first be opened and then saved using AppleScript Editor, which is located in your /Applications/Utilities/ folder. More information is here.)
Use tag data to formulate new file name for selected tracks' files
Export selected playlists as individual XML or M3U files
Perform search-and-replace on text in your choice of tags
Set the Plays of selected tracks.
Displays files in iTunes Media folder not in iTunes track library
Remove iTunes tracks disassociated from files