That's all you have to do and I would highly recommend it. I have been paying the $25 "international data" plan for a couple of months and was recently in the UK for THREE DAYS. I turned off my data for one of those days. Turns out that in just two days, I blew through the "international data" allotment (what a joke) and was charged another $125 for the overage. And this was without once using Safari -- all email. Unreal. Before joining ATT for the iPhone, I was with TMO. They had their quirks but I miss them still.