There is a hardware hack
There is a hardware hack for your beloved iphone, i believe it works with all mobiles, and it does not mess the phone up you can continue to use itunes etc. It is called the Rebel Sim Card and it is a thin shim that fits between the phone and the sim card and it fools the phone into thinking it is still on the network it is locked to. I still have the review of it that was in PC Pro June 09 where the auther used an iphone with a Vodaphone sim and was still able to access itunes and the app store with no problems. And it leaves the phone in its original state.