Use a service you can find easily on Ebay. Search for this: blackberry 8100 unlock service vodaphone
greetings check out www.crackberry.com they have forums/help for every bb device just go to the 8100/pearl thread and check out your issue. every question is posted and answered..
Unfortunately, it's not possible to configure it without adding the plan. Trust me, I tried that already. Your handheld has to be registered with the BlackBerry network in order to use WAP and regular browsing services.