The video is over WiFi, but the call still goes through AT&T. It will use the same minutes as a regular call...However, it is only supposed to work from iPhone to iPhone right now so chances are the person you are calling is with AT&T. If you have AT&T and so does the person you are calling, it is still included under the unlimited mobile to mobile. If the call is from your AT&T phone to a jailbroken iPhone 4 under a different carrier then the call would use the same minutes as a regular phone call.