I know a lot of people who use an AT&T mvno on their iPhone. But recently, h2o went down the drain, downgrading their $60 plan to only 1GB of data a month. I switched to Red Pocket which has 2GB data/month (along with unlimited talk&txt) for $60. I ported my number from h2o to red pocket and I'm very satisfied with the service. No unlock needed . Very affordable + you get that AT&T 3G. Heres a quick video I make talking more about it and showing a speed test: Do you use an AT&T MVNO on your iPhone?