[Keme]

If you’re a windows user, the best program in my experience has been mediamonkey

great series of articles at lifehacker.com

http://lifehacker.com/software/album-art/alpha-geek-whip-your-mp3-library-into-shape-part-iii-metadata-233336.php

[kingu]

A second on the MediaMonkey program.

My second favorite feature (after the ID3 editing abilities that are easy and quick, especially on large groups of files) is the ability to transcode to different formats when synching. Third favorite is the media library features that help me organize my files.

[Marak]

Thanks for pointing me to MediaMonkey. It appears to be an excellent program, but it does not appear to be able to toggle the copyright bit.