CBS and NBC have announced deals to offer replays of prime-time programs for 99 cents per episode, shifting television toward a sales model that gained popularity with downloaded music.

CBS is teaming up with Comcast Corp. (CMCSA) and NBC with satellite operator DirecTV (DTV) to offer the on-demand replays.

NBC Universal will offer commercial-free episodes of "Law & Order: SVU" and other shows to subscribers of DirecTV Group Inc. who use the satellite company's new digital video recorder.

Comcast's on-demand customers in some markets will be able to view "CSI: Crime Scene Investigation," "NCIS," "Survivor" and "The Amazing Race" at their convenience.

Terms of the deals, which were announced Monday, were not disclosed.

"This is an incredibly exciting evolution for CBS and network television — video on demand is the next frontier for our industry," CBS Chairman Leslie Moonves said of the deal with Philadelphia-based Comcast, the nation's largest cable systems operator. CBS, which is owned by Viacom Inc.(VIA), announced last week it would stream episodes of its show "Threshold" over CBS.com.

The Walt Disney Co.'s (DIS) ABC network offers downloads of several programs, including "Desperate Housewives" and "Lost," for $1.99 each via iTunes software from Apple Computer Inc. (AAPL).

Less than three years ago, Apple helped spur the explosion of legally downloaded music with its iTunes Music Store and iPod portable players — the latest versions of which now play video.

Comcast's service will be available starting in January to customers in markets with a CBS owned-and-operated television station, which includes the nation's seven largest media markets. The episodes will be available as early as midnight following a broadcast and will include commercials.

The DirecTV agreement includes shows that air on NBC, USA, Bravo and the Sci-Fi Channel, including "The Office" and "Monk." Episodes of the shows will remain available for one week after their broadcast. NBC Universal is a unit of General Electric Co. (GE).

DirecTV, which is based in El Segundo, Calif., and controlled by the media conglomerate News Corp. (NWS), began shipping its new DVR this week. The device uses interactive software from NDS Group Ltd., another News Corp. unit, and is designed to transition the company from dependence on similar devices made by TiVo Inc. (TIVO).

"We are talking to the other networks and hope to reach similar agreements soon," DirecTV spokesman Robert Marsocci said Monday.

The new DirecTV DVR comes with a hard drive that holds 160 hours of programming. One hundred hours are available for subscribers to record and store programs. The remaining 60 hours will be used by DirecTV to download programs that can be viewed on demand for an extra fee.

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