I have an unlocked iPhone 4 that I'm planning on using on T-Mobile. If this NanoSIM is available at a store near me, will I be able to purchase it and use it for the $30 Monthly 4G plan that's available through the website or will I still have to buy the regular MicroSIM through the website and eventually cut it down to nano?
The iPhone 4 uses a Micro SIM. The iPhone 5 uses a Nano SIM, which is smaller than the Micro SIM. T-Mobile stocks both types of some cards so you should be OK using either iPhone with T-Mobile.