is there any good free audio editing software?

I want to be able to take music I have (legally) and change it around like remove the vocals or take out the bass and all that jazz.

Audacity http://audacity.sourceforge.net/

You are probably going to need to install Lame as well, so you can work with mp3's. http://audacityteam.org/wiki/index.php?title=Lame_Installation
i second that. audacity is the best program. not to mention that it is open source.