July 27, 2011- Vonage has introduced a service enabling subscribers to extend their VoIP service to additional phone numbers and devices, including mobile handsets.  According to the press release, “Existing customers can add any U.S. phone number as an extension by logging into their online account. The extension phone number can be a cell phone, a home phone or even an office number. Once registered, the service works like a virtual calling card.  Simply dial the access number and international destination number and the call is connected over the Vonage network.”