Using an iPad in the USA

[US020]

Good morning all

Just wanted to know how I could go about using 3G in the USA?

I've seen say for example some Three 3gb loaded sim cards... could I take it over there and use that?

Anyone had any experience with this?

Will be using wifi as much as possible of course, however would be nice to be able to use the 3g function.... just i'm not sure how to!

Do you buy a sim in the USA preloaded or better to buy here before you go?


Thanks