I've just got Logic Express 7.2 from my local store, I installed it, but if I connect my Korg TR 88 to my mac, I can only use the GM bank. Where can I find the instruments of my Korg in Logic? Please help

You'll probably have to program your own custom multi-instrument, which isn't hard, though it is time consuming. You could also check the web, or even Korg's site to see if they have some pre-configured Logic Multi-Instruments. In the past, korg has been pretty good at this ... not sure if they are still ...