I bought my iPhone from the AT&T store in Ohio back in the spring of 2008. It was locked and I bought (and still use) the ATT data plan that accompanies the iPhone activation. I am now visiting Thailand, and decided to take the plunge and unlocked my iphone in order to be able to purchase a Thai prepaid SIM and make calls to the USA. I didn't want to be bombarded with insane ATT phone bills. My iPhone was the most up to date so far, with version 1.1.4. I return to the US in a month. I don't really care about the other perks that locked phones have to offer. Therefore, when I return to the US, and put my original ATT SIM back in the phone, will I still be able to use the phone like I used to before it became unlocked? Will updating it via iTunes relock the phone? I personally wouldn't mind if my phone became relocked, but I am curious if this is possible. And another thing... if my phone can never be relocked, what are some fun things I can do with the unlocked phone other than operate it with different carriers? I know I should have looked more into this before getting it unlocked, but I'm impatient... :-/ Any help would be much appreciated! Thank you!