Cablevision, which provides cable TV service to some 3 million households in the New York metropolitan area, launched a residential VoIP service offering unlimited local, regional and long distance calls throughout the U.S. and Canada for $34.95 per month. The "Optimum Voice" service includes five premium calling features: call waiting, caller ID, call return, three-way calling and call forwarding. Optimum Voice works over a cable modem with household electricity as its power source (no back-up). International calling must be made via prepaid...