Macbook Pro OSX 10.7.2 and Oxygen61 Midi Controller Keyboard

Question 1. I thought this midi device (M-Audio Oxygen61 USB Midi Controller was "Plug & Play"? It does play but none of the keyboard's slides or knobs have any effect on adjusting anything, I have attempted to "Download the Drivers" from the M-Audio site.

I am new to Macs (Former PC user) and don't know if I am doing something wrong, or where to go next?

Question 2. If you open an iTunes song in garageband and drag it over as a track to play along with, how would I go about transposing (May not be the proper term) the keyboard to match the exact pitch or key of the song being played from the iTune file appearing as a track? I was able to do this with a PC. Is garageband capable of this? Suggests if not?