I tried to jailbreak my iPhone 3G on 2.2 using quickPwn on OSX
everything was going fine until it told me to put it in DFU mode.
I followed the onscreen directions and it hung on "QuickPwn is about to go on your iPhone 3G".
After this my only choice was to restore back to 2.2 with no jailbreak.
It won't restore iTunes prepares it for restore and then I get this error:

This leaves me to disconnect it, turn it off and try again.
I've tried more than 5 times.
Can someone please help me with this?

er i tried jailbreaking my friends iphone and the same thing happend

try holding power and home for 10 seconds then releasing power whilst still holding home this should reset the iphone if its faulted

worked for me hope the same happends for you