So, its been only a couple of weeks after the iPhone 5 launch and T Mobile was probably the only cellular service provider in US that did not have a tie up with Apple. But it has proactively been aggressive about wooing all the unlocked iPhone5 users.
T-Mobile has introduced its latest range of nano sims specifically made for iPhone5 so you can grab one and use with your unlocked Verizon iPhone 5. There are no “official” unlocked iPhone5s from Apple so far, but people have already figured out that the Verizon iPhone 5 phones that are available from Apple stores (About $750 for a 16GB) are already unlocked, that you can use other sim cards in it, even while traveling abroad.
Here is a video showing how to use the new T-Mobile Nano sim cards on the new iPhone 5 unlocked (Verizon).