Apple Users

Thanks for clearing this up. Calling home when I'm overseas is exactly what I need to do - preferably without having to pay an exorbitant fee.

When I looked up "Wi-Fi calling" on Wikipedia, my search was redirected to "Generic Access Network". One problem is that I don't understand the Wikipedia article. Therefore I would like to ask some more naive questions.

When a smart phone doesn't have Wi-Fi calling or something equivalent, does that mean it can be used for web surfing and e-mail, but not phoning, via Wi-Fi?

My current phone is a Blackberry Bold 9700. Whenever I'm connected to Wi-Fi, I can make a phone call. I guess this means I already have Wi-Fi calling. The phone uses GSM and works in Europe. If I call home from Europe using Wi-Fi calling, do I just dial the same number of digits I would use when making a local call at home, or do I have to dial something else (e.g., a country code) first?