RealPlayer?

Does anyone have any idea how to compress files on realplayer?
I'm trying to do it in order that i can apparently fit ten cds on one!!
any ideas anyone?

http://forms.real.com/rnforms/products/too.../producerbasic/

but in all honesty, real media is crap
use mp3

Okay, thanks for that...a friend of mine has just told me i can do it on media player?
for windows?