The Verizon Wireless LTE Phones run on the new 4G network and if you wanted to unlock the phone to put it on an ATT network will not work. They say the phones are going to be on a different frequency and would not be compatible with other networks.
Verizon may be designing its phones to only run on Verizon’s very specific wireless frequency, locking out all other possible carriers. Verizon and AT&T both run their LTE networks in the 700-MHz band. But Verizon’s network is mostly in 746-787MHz, while AT&T’s will be primarily in 704-746MHz. Some Verizon and AT&T spectrum overlaps in an area called the “lower B block,” but not much. Verizon could build its phones to exclude AT&T’s frequencies, and vice versa.
Personally I am not a big fan of unlocking phones and bringing it to other networks and with the iPhone on both major networks and Android making all types of phones for both networks I would think the 4G phones are going to be very similar which means unlocking phones really won?t even be truly needed in my opinion.