i want to unlock iphone4

Posting the same question more than once won't give you a different answer!! As I previously stated, contact your carrier, only the carrier to which your iPhone is locked can unlock it.

Contact the carrier to which it is locked, just as you were already told.

It depends, ATT is the only one that can unlock the phone. And only if it's out of contract already.

gugabackahnd wrote:

It depends, ATT is the only one that can unlock the phone.

Unless AT&T is not the original carrier. The OP has never stated to which carrier the phone is locked.

I had the same question aswell, but after alot of research I found out that only the carrier your iphone is locked to can do an authorised unlock. Hope it answered your question.

Not sure why "a lot of research" was necessary. That information has been given in these forums many, many times, and was stated clearly by two different people in this thread two months ago.