Yes you can unlock IPhone from AT&T NETWORK lock ..But they don't charge for using other network like T-Mobile and their services...They charge only to unlock the i-phone..AT&T provide unlock code at cost only.Also they will not give it soon..They ask to wait for some days or even months..So better get the Remote unlock service for I-phone at Superunlockcodes.com and unlock it from network lock easily.Then use with any GSM Network sim card .