Did you turn off usb debugging?
menu > settings > applications > development > un check usb debugging
don't forget that you also have to mount the sd card via the phone after plugging in the cable.
For the 2.2 upgrade, different drivers are installed along with the upgrade tool. Make sure to clear off any other samsung usb drivers that may have been installed. Follow the update tool's directions. If the install seems to stall out after starting the upgrade (you'll see a progress bar) wait a few minutes and if it doesn't move, un plug and re plug the cable. It says specifically not to do this, but I've found it works to start up a stalled install. Good luck!