How to unlock an AT&T iphone 4 if I'm not an AT&T customer?

I ordered an at&t locked iphone 4 off of ebay yesterday, with the sole purpose of unlocking it so I can use it on work trips overseas. I do realize that you can go through at&t and unlock it, but the thing is, I'm not an at&t customer. Will they help me with the unlock even if I'm not their customer? If not, how else can I go about doing this?

Iphone is the most pain in the *** to unlock. I will give standard instructions that work for any other phone. The iphone almost certainly needs to be unlocked through itunes at the AT&T store. You need the IMEI number. To get the IMEI number you can either dial *#06# and it should pop up right on the screen or you can take a peak under the battery. Since you can't take the battery out… That's iphone for ya.

Make sure it is an ATT phone cus if it happens to be verizon your SOL!

Once you have the IMEI number you need to get the unlock code. You can find them on ebay usually for really cheap. Iphone again not easy to find unlock codes… Once you purchase an unlock code you need to use a non AT&T sim card such as T-mobile (or anything else). Now iphone came up with the micro sim cards, regular sim cards won't do so again pain in the kister but not impossible. You need to either order a micro sim card from the company that you want to use or you can buy a sim card cutter for $10. Once you have the sim card cutter, cut the sim card and be careful not to damage the metal surface. The cutter will cut the card down to the exact size.

So, once you have the unlock code and a sim card cut to size replace the att sim card with the sim card that you just acquired and turn the phone on. Unless iphone has some special way of doing this (which I think it might) a message should pop up on the screen saying please enter sim unlock code or subsidy unlock code etc. Enter the unlock code and presto. You got yourself an unlocked phone.

Now, I'm pretty sure that the iphone 4 is a world phone capable meaning that the 3g should work everywhere but you should probably double check. The phone's 2g will work just fine.