iTunes only allows one playlist to be selected at a time. This applet can perform common useful tasks on a multiple selection of playlists: rename (add text, remove text, search and replace text), duplicate, delete, export, merge.
OS X 10.6 or later only.
Tools in the Rename tab operate on the selected playlists' names
Create a Ringtone track from a selected track
Search for lyric sites with Google using info from the current or selected track
Change selected tracks' Start Time or Stop Time by user-entered seconds
Increase or decrease ratings by a half-star
Drag-and-drop to convert audio files with iTunes
Correct song titles listed as "Artist - Song Name"