Las Vegas - Comcast (NASD: CMCSA), the nation's largest cable TV provider, on Tuesday announced plans to launch Wideband, a high-speed download service that promises to deliver full HD movie downloads in just four minutes. "Wideband takes four channels and bonds them together and will enable speeds to go up from 12-16 megabits a second to over 100 megabits a second," Comcast CEO Brian Roberts told Reuters. "If it's as successful as we plan we'll roll it out to tens of millions of home shortly thereafter."