Is google voice free when I travel to Europe?

I'm going to London tomorrow. I have AT%26amp;T service. If i want to make outgoing calls, can i call my google voice number and call whatever number I want for free? When I pick up incoming calls from my google voice will it be free as well? THANKs|||It will be free from google but hey u''l still be charged for the roaming,be careful it can be very high.Even google will be free still u will/can be charged for incoming and outgoing both with high roaming rates.Just ask ur AT%26amp;T service support for all the info.