Transfer music

On my iPod I have music from other libraries as well as mine so when I sinc with my iTunes it will delete the music that isn't on my computer.
How can I transfer the music I got from other people from my iPod to my hard drive so that I can then add it to iTunes?is there a program that will allow me to do it?
I used to use CopyPod but I can't find a version for mac...do you now if there is a similar program?
thank you very much...

Try iPod Rip (shareware - can be used 10x for free first though.)
www.iLounge.com has a large library of iPod related software (mac & windows) so maybe look there for other free alternatives.

Just to point out what you're asking to do is illegal.

Schweb is right of course - if the music libraries you're copying contain copyrighted music, then you aren't allowed to do this.

But you're probably sharing Creative commons licensed music right? Or stuff that the artist allows you to share? Like the stuff you can find at www.ampliphonic.de/media/sound/

btw, i think the best ipod coy util is probably senuti...find it on versiontracker.com