Need Xmas Help! - New LG VX7000 on Ebay

I'm buying a new cell phone on Ebay for my boyfriend for Christmas. It's the LG VX7000. We already have a family plan with Verizon and a little over a year left before we technically "allowed" to get a new phone. SO, my question is: How do I switch his number to this new phone so that it'll work for him? Is there something I can just do with the phone myself or do I need to take it to the Verizon store for them to do it for me? It is an unlocked phone by the way, whatever that means. Sorry, I'm not that up to date on this cell phone lingo. Any help though I would GREATLY appreciate before Christmas is here! lol Thanks for your time!

-Liz

if you buy a phone on ebay and its been "unlocked" just take the old phone and the new phone into a verizon store and ask them to transfer the ESN # to the new phone. It costs money to do this and also you would want the phone book transfered which also costs some more moeny