By Richard Martin

Comcast Corp. (CMCSA), the nation’s No. 1 cable provider, has agreed to purchase privately held VoIP provider New Global Telecom Inc., according to industry sources. The purchase marks the first major acquisition of a VoIP provider by a top-tier cableco.

Comcast president of business services Bill Stemper sent an e-mail to employees today announcing the purchase. Our sister site, VON, has acquired a copy of the memo.

“I am very happy to announce that Comcast has signed an agreement to purchase NGT (New Global Telecom), one of the nation’s largest providers of wholesale hosted and trunk-based VoIP solutions,” Stemper wrote. “The win-win for us is that we have purchased NGT because of their innovative features and employee expertise. I strongly believe this acquisition will help us take another progressive step in achieving our goals.”

Based in Golden, Colo., New Global Telecom provides services to carriers and competitive service providers in the U.S. The company has recently announced a series of private-label deals, under which NGT supplies branded VoIP services to operators like American Broadband Inc.

Comcast, which has about 24 million cable subscribers, has made a strong push into both telecom and online video services in the last year, attempting to become the leading provider of quad- and triple-play bundles into American homes. In late 2009, Comcast became the first major cableco to launch its nationwide broadband on-demand offering over the Internet. Known as “Fancast Xfinity TV,” the new service is available to customers who subscribe to both Comcast’s broadband Internet service and its cable TV service.

The company has also agreed to acquire NBC Universal, in a $30 billion deal that is undergoing intense scrutiny from federal regulators.

As of this writing, Comcast and NGT executives have not officially responded to requests for comment. We expect to post further details later today.