I have found your forum as a result of mistakenly renting a holiday home in Florida with no internet access!
I own a UK purchased iPad that runs mainly on WiFi but has an Orange data microSIM that has no contract or prepayment. Literally I'm charged as I go monthly and have yet to exhaust the £10 free starter. This forum has given me invaluable help reference AT&T's offerings so I am off to the relevant thread in a moment (if i can find it) to raise a couple more queries.
I love my iPad but I do want to scream about the browser. It is a tragedy Apple are so intransigent about Flash!