Should work just fine on wifi, where available. Your cell phone won't be able to make/rcv phone calls due to the incompatible cellular networks but wifi would be no issue. Verizon won't bill you anything for using wifi while there. Text/picture messaging won't work either but you can check email while connected via wifi.
I'm traveling to Italy where there is no service for my Verizon droid phone, but I have Google voice on it. If I am in a wi-fi hot spot, can I make or receive google voice messages or calls? what other functions will my phone have while I am there.