verizon says they unlock phones once a year or something, i am sure ymmv based upon which rep you get. the global reps always seem to be the most knowledgeable.
if you are just going to use verizons service abroad, you can just call them to activate the plan.
if you are planning on using a foreign micro sim: first, call verizon and have them get the unlock code from apple (while in the states). it shouldn't take very long.
second, after inserting the foreign micro sim the phone has to connect to the internet to activate the sim or connect to itunes. and the unlock pin will come with the sim.
i just bought a noosy micro sim cutter to take with us from amazon because it was hard for us to find a store with a cutter in spain.