Hey KFAIProg, Welcome to AM! The best place to find prog CD's is online.
See the following sites:
Kinesis:
http://www.kinesiscd.com/
The Laser's Edge:
http://www.lasercd.com/
Syn-phonic:
http://synphonic.8m.com/
You could also try Amazon for some of the more available stuff (but you still might have to special order it).
Also you should check out
http://ghostland.com/ to learn more about prog music.