If you are looking to use another networks SIM card in your iPhone 5, roam internationally and make cheaper calls then you may want to consider the R-SIM7. This new SIM card unlocking solution promises to unlock any model of the iPhone 5 or iPhone 4S running the iOS 6.0 / iOS 6.0.1 firmware. There is no Jailbreak required, and apparently will work with any baseband version.
R-SIM7 works by simply inserting both your SIM card and R-SIM7 into your iPhone, going into Settings > Phone > SIM Applications and then configuring the options present like selecting the carrier you are trying to connect to. After the settings have been configured you restart your iPhone and it will work with the chosen carrier.
It is noted on the official website that if you have a CDMA version of the iPhone you must install their auxiliary patch to iTunes. Other than that it appears R-SIM7 is a hassle free unlocking solution for your iPhone 5 or iPhone 4S running iOS 6.0 / iOS 6.0.1.
If you are interested in the R-SIM7 you can purchase one for $23.90 for a limited time.