Ok well there are a few way to go about it, easiest first would probably be usings htc's network wizard and selecting AT$T
The next would be using a tweak program such as advanced configuration by shap's selecting my isp and deselecting media net and while your there I like to click always stay connected mostly for my push email and weather.
Oh and if you like my help and what I do for this site
Vote Nate for Admin so I can better help you all by being an admin it would make encoding links avialable like youtube and such so you can get an instant visual as you read my program post.
http://www.pocketpcaddict.com/forums...html#post60243