Guide to Unlocking your iPhone
by Guggu V
Unlocking is the removal of SIM restrictions on the modem, allowing the use of the iPhone on any carrier. The main reason to unlock your iPhone is if you want to use it with a different service provider (ie T-Mobile). Update: Sadly, unlocking iPhones by third-party methods has become illegal in the US if you bought your iPhone after Jan 25, 2013.