I was looking into this forum for other info and saw mass confusion so let me clear the air in here.
An msl code is NOT an unlock code. Unlock codes are 8 digits or more. Msl codes were used in flashing a phones software, which due to all newer devices taking sim cards, it is a worthless technology or thing to do, getting the user only 3g typically.
IPhones do NOT take an unlock code at all to unlock (almost all other makers do).
IPhone 5 can work here in the US if you unlock it (bought 3 from sprint on ebay and 1 was unlocked and worked fine with metropcs). Haven't tested the sprint lies on a 4s yet though.
Carriers are NOT the only ones unlocking phones. Both the carrier a d the maker can and if you pay hundreds to thousands of dollars like I have, you can buy a box that can do everything for you through software.
Right now iphone sprint unlocks are one of the lowest prices running, with a clean esn of course. This is not a plug for me to make money. Feel free to ask me more on all this.