iPhoneSimFree was the first to release a software unlock program for iPhone, enabling the device to work on any compatible GSM carrier. And, while their update did not brick iPhones, they have been working ever since the 1.1.1 update to fix all iPhones.
The free SIM unlock process, anySIM/iUnlock, themselves a reverse-engineering of iPhoneSimFree’s process, was identical in performance… until the 1.1.1 update. The update, according to Apple, would “permanently damage” iPhones unlocked with anySIM. However, iPhones unlocked with iPhoneSimFree, were simply re-locked to AT&T SIM cards.
Today’s release from iPhoneSimFree both re-unlocks iPhones updated with 1.1.1, and fixes iPhones that have been unlocked with anySIM. iPhoneSimFree is available from retailers linked on their web site, usually for $99.