You could convert them to lower bitrate using freeware tools from the internet, but I would not recommend doing this, as the quality will also be decreased. Also if you decide to do so then please do not share them on Limewire.

I would suggest either burning them as data to CD-ROM/DVD or getting more space, like eg. an External Harddisk

Incase you still want to do this then:

http://www.msfn.org/board/lofiversio...hp/t81908.html

(For mp3 BTW. You don't mention what format your music is in)