I came from a black berry, where if you joined a wifi, your calls would route over the said wifi (tmobile). I was under the impression that when an iPhone is connected to WiFi and you make a call, you are making it also under wifi. Case in point, my house has no 3g or edge coverage in the basement. Since I installed wifi and connected my iphone to wifi I can make calls without issue. A friend told me all voice calls are made over Edge or 3g and have nothing to do with wifi. So which is it? Anyone know. I am not talking skype. I am talking the native iPhone app for calls. Thanks!