From Dennisski81.
I have the IPone GS3 and cannot get it to tether to my iPad 2. I have had a second session with AT&T and they concluded, for a second time, that the Iphone 3gs will not tether with Ipad2. pAfter spending a lot of time with AT&T, I changed my account to access both Hot Spot and Bluetooth tethering. The Iphone3 would connect only for a short time, then disconnect on the tethering and would not reconnect. Working with AT&T, they researched the problem through three different levels, and came back with IPhone3 does not work with tethering the IPad 2, unless I wanted to wire them thogether through ups cable. To do that, I would have to turn off the WiFi on the Iphone. So I changed back my account to the less expensive ($15 dollars/month) 2 Gig service.
Please let me know if you have another solution.