As of version 4, iTunes has a "Replace Existing" option when users are re-importing CD tracks to replace existing tracks. The problem is that iTunes will only allow this option if the ID3 info for the CD tracks and the current iTunes tracks is identical. This script writes the writable info from selected tracks to the info of a CD; when you re-rip, the CD track data is already the way you want it.
(Note: In order to launch this PowerPC-era script on an Intel machine, it must first be opened and then saved using Script Editor (AppleScript Editor pre-OS X 10.0) which is located in your /Applications/Utilities/ folder. More information is here.)
Select iPod tracks in iTunes and add them to iTunes
Display the width x height of selected track's artwork
Two scripts copy text from clipboard to current or single selected track's lyrics tag
Create a text file containing an alphabetical list of chosen tag data
Export info to HTML doc
Locates pairs of track entries pointing to the same file