Help Unlocking iPhone 4s (Verizon) for International Use

Hello,

I'm moving to Germany and am trying to figure out how to SIM unlock my phone for permanent use in Europe (Germany). I'm not concerned with using the phone in the US with an American carrier, as I've heard that can be problematic. I have an iPhone 4S from verizon that is no longer in service - I cancelled the contract last summer when I was given a work phone. I have read the instructions for having Verizon SIM unlock the phone, but that seems to only be possible if the phone is still in service, and mine is not.

Does anyone know of a way that I can unlock my phone and be able to insert a SIM from a german carrier when I arrive in Germany? I'm willing to do it myself if it's not too complicated.

Thanks!
Sarah