I own a 8320 and i recently got a 12MB internet plan. I have only been able to connect to the internet using wifi. When i go to 'Options', Advanced Options', 'Browser' to change the Default Browser configuaration from wifi it does not give me any other options.
If you also have BlackBerry Email and Browser plan then I am sure you should be able to get the BlackBerry Internet Browser.
If you do but you dont have the option tyhe try:
Go to Options then Advanced Options
Scroll and select Host Routing Table
Press Menu on the HRT Table Editor and Select Register NOw..