Andy posts long and loud on AT&T’s new Unity Plan: unlimited free calling between AT&T mobile and landline customers for a fixed price per month.  While the plan excludes mobile roaming, international calling, and CallVantage services (the AT&T VoIP offering), he thinks they will be blended into the mix soon enough. This should prove troubling for companies like Vonage. In fact, why use Vonage when I can have unlimited mobile AND landline calling for a fixed price on one monthly bill?