I am looking into buying an iphone. I hear there is a new 3G version of the iPhone due for release in next month (June). I have read about many of the benefits of the 3G iphone. My question is this: If I were to buy a 3G iphone I would most likely unlock it and use my existing 'pay as you talk' sim card. If I were to do this, would I still benefit from the new 3G technologies? Or is 3G only available to O2 contract customers?