Does this allow you to play CDs? I'm looking for a program that will allow you to cut and loop parts of songs off of a CD.

My mobile-pre came with a watered down version of Ableton Live (http://www.ableton.com/) that should allow you to do this. I didn't really try it out much as it seemed to be geared more towards electronic music.
If you just want to do loops and don't need the interface you might want to look at Acid from Sony. There's even a free version called Acid Xpress. http://www.acidplanet.com/tools/?p=acid&T=487