002 has stand alone support 003 does not. I always have to be careful as I've said that wrong before, you would think the 003 would add functionality not take it away, it was quite a disappointment to some folks when the 003 came out without it. Well discussed on DUC in the past, and wait for it... well described in the product guides
Look for "stand-alone"
http://akarchive.digidesign.com/supp...d_with_002.pdf