why not save that $100 (since you have access to CS4, yes?) you were going to spend on software and by the nifty fifty? That is the "cheapo" 50mm f/1.8 that Canon makes that sells for about $90 new? It IS a must have for any photographer. Ya know, i took a photography class (part of my degree i am earning) and it really didn't teach me anything new, however, it wasn't worthless....
The best thing that you can do is read the manual of the camera several times, and go to a book store and sit down and look through some books. It really doesn't matter is the book isn't the newest "digital" book or is 3-4 years old, the subject matter in the book doesn't go bad.
I think spending money on a class at this point isn't necessary. Go out and shoot. Now if we were talking about film, I would say that would be a good idea. Shooting digital doesn't cost you a thing, as far as developing or if you come back with bad photos. Don't be afraid to mess with different aperatures, exposures, etc...
I just say practice, practice, practice, and read. Classes with teach you lighting techniques, exposures, aperatures, etc. I say after practicing for a while and you still feel uncomfortable, than spring for a class. I mean it can't hurt.
I am no pro by any stretch of the imagination, but persistance and practice can yield great results. These were shot with a 30D (basically a 20D, which is what you have) and a 10-22mm lens, which cost about $600, not too expensive...