The service comes less than three weeks after NBC Universal said it was pulling its programs out of the highly successful iTunes service of Apple Inc.
That partnership fell apart because of a dispute over Apple's iTunes pricing policies and what NBC executives said were concerns about lack of piracy protection.
NBC's move comes as companies throughout the television business search for new economic models in the face of enormous changes in the business.
Networks continue to lose audience share, and viewers - especially many of the highly prized viewers under 30 years old - are increasingly demanding control of their program choices, insisting on being able to watch shows when, where and how they want.
At the same time viewers are finding more and more ways, like TiVo machines, to avoid watching the commercials that have long provided the bulk of television revenue.