RatingStar will help you create backups of your iTunes song ratings. It will also help you to restore backed-up ratings to iTunes. If you export your ratings to a file you can edit it outside of iTunes and even import it to another iTunes library or playlist. Options include backing up from iTunes or iTunes Library XML file. Ratings can be stored in a delimited text file or in the music files' comments tag.
What's new in this version:
Version 2.0 adds a new tool to set song ratings to a default, and support for Windows Vista and Windows 7 RC.