But theres a new wrinkle that potentially makes the international-roaming experience better on Sprint and Verizon iPhones than it is on AT&T. Sprint plans to sell the iPhone 4S with its micro-SIM slot unlocked; Verizons will be initially locked, but if youve been a customer in good standing for 60 days, you can call Verizon and ask for an international unlock. (A Verizon spokesperson told me that this is Verizons standard policy for all world phonesits just the first time its manifested itself on an iPhone.)