I'll be heading to the US in a few months and I have an unlocked iPhone 4 that I'd like to be able to use while I'm there. I've read here and there that you can put in a AT&T Gophone prepaid sim card into the iPhone with no problem and be able to access data too.

To those who have done this in the past, I have a question. Are you able to tether your phone to say your laptop either via bluetooth or via USB so that you can access the internet?

I'd like to be able to do this as I will be taking long train rides during my trip and would like to be able to access the internet on my laptop while I'm on the train.