Set the Plays ("Play Count" before iTunes v9.2) of the selected tracks to a user-entered number (they will all be set to the same number). If this number is 0 then the Last Played date of each track will be erased. (iTunes has the ability to "Reset Plays" to 0 from a track's contextual menu.)
Also see New Last Played Date and Add or Subtract Play Count.
Perform search-and-replace on text in your choice of tags
Copy Artist to Album Artist of selected tracks
Export files of tracks in two or more playlists to single folder
Remove iTunes tracks disassociated from files
Convert selected tracks and export the converted files to a new folder
Apply selected CD's CD Text to its disc and track tags