I finally got my 3gs unlocked and working in China. Phone Calls, SMS, and Data are working, just need to determine mms setings for China Mobile Easyown.
Here are a few points of my experience
-Must have a sim installed, I used my China Mobile Sim
-Must be in the US, I had to use my US VPN when plugging into iTunes to get the unlock to work while I am in China
-The backup and restore can be done in advance, and the unlock will occur when you plug the phone into iTunes later. In my case when I plugged into iTunes with my China Mobile SIM
-It took a few days from my original call to ATT for the unlock to work as I tried in the US with an old ATT sim before leaving for China. It might also require that you use the non-ATT sim (I don't know for sure).