This is an easy to solve problem. Duplicate phone functionality: Let the user decide which number they want to dial from by changing the Settings on the iPhone

This is an easy to solve problem. Duplicate phone functionality: Let the user decide which number they want to dial from by changing the Settings on the iPhone and thus making the iPhone capable of making and recieving the phones calls from either AT&T and Google. Voicemail: Let both AT&T and Google store the voicemails at their own servers and push them down to iPhone. SMS issue: Solution is same as voicemail. Let the user decide which number they want to send the SMS from, and let both Google and AT&T deliver the SMS to the iPhone Messages app. This solution will allow for flexibility for both the users and the service providers.