Currently the 3G iPhone sold in the US cannot be unlocked to use a foreign SIM (unless someone has managed to hack it).
I live in the US, but spend 6-8 weeks of each year in Ireland. Up to now, I've used different phones in each country (Sprint with a monthly fee in the US; another cellphone with prepaid cards in Ireland), but I'm thinking of thinking of taking the leap and buying an iPhone 3G so that I can use the same phone all the time.
My main concern is the cost, and I'd like to make sure I'm doing everything I can to make this as cost-efficient as possible. It also looks like I'll have to pay a Sprint termination fee of $200 or so, because I have a year left in that contract.
I understand that international roaming is expensive, and would like to avoid those fees if possible. I also understand that it's far cheaper to purchase the iPhone 3G here in the US.
So - is signing up for AT&T and purchasing the iPhone 3G here, along with the plan they offer, the only way to do this? Would it be feasible/cost-efficient for me to buy the phone individually from the Apple store, and unlock it myself, and upgrade my Sprint service to include data to accommodate the iPhone?
Would it then be possible for me to switch out the SIM card when in Ireland, and use a prepaid mobile card there?
Thank you in advance for your help!