Two broadcast television networks announced deals with cable and satellite providers Monday that take a big step in that direction.

Ratings leader CBS has struck a partnership with Comcast, the largest cable provider in Utah, to broadcast hit prime-time shows such as "CSI: Crime Scene Investigation" through Comcast's On Demand service, a feature that allows subscribers to pick a show from a list and watch it anytime.

Rival NBC announced that it had secured a similar deal to provide some prime-time programming through an on-demand service with satellite provider DirecTV.

Both services will charge 99 cents per show, which will be shown commercial-free. The episodes would be available just an hour or two after they air on regular TV. In most cases, shows would be available for a week and then taken down when new episodes air.

The partnerships come on the heels of another groundbreaking deal announced last month, in which ABC and Apple Computers will make hit shows "Desperate Housewives" and "Lost" available for download through Apple's iTunes music and video service for $1.99 each.

"We see this as a huge value for our customers," Comcast spokesman Ray Child said Monday about the deal with CBS. "On Demand is growing by leaps and bounds, and that's what makes it compelling for CBS to get involved."

CBS is making "CSI," the Navy drama "NCIS" and the hit reality shows "Survivor" and "The Amazing Race" available on Comcast's On Demand. For DirecTV, NBC is providing "Law & Order: SVU," "Law & Order: CI," "The Office," "Surface" and cable hits "Monk" and "Battlestar Galactica."

Both services will begin early next year.

Comcast has offered On Demand to subscribers since last October, providing more than 4,000 hours of free programming from cable stations such as HBO, Showtime, Animal Planet and the Discovery Channel but not prime-time series from the broadcast networks.

The programming is stored on computer servers in Comcast's Sugar House office, and viewers can call up a show to watch whenever they want. The video is streamed to customers' homes through a digital receiver box they rent.

DirecTV's system downloads the programs to the customer's receiver box where it's stored on a hard drive in the middle of the night. Ordering the program for 99 cents "unlocks" it for viewing. The new DirecTV receiver boxes are shipping to stores this month, said company spokesman Bob Marsocci.

As this new form of television distribution takes hold, one of the biggest concerns is whether it will affect the number of viewers who tune in to the shows at their regular times.

David Phillips, general manager of KUTV Channel 2, the CBS affiliate in Utah, doesn't think TV ratings will be affected.

"The effect is going to be similar to what we see with TiVo. They [TiVo and on-demand users] record what they normally wouldn't be able to watch and watch it at a later time," he said. "They aren't really viewers you get week in and week out."

In fact, he hopes making the shows available through on-demand services will help.

"The more eyeballs I can get addicted to that product, the better. I almost look at it as marketing."

Video On Demand: How does it work?

Comcast: People who subscribe to Comcast cable order episodes of a network show from a menu and pay 99 cents per order. Certain cable programming is already available for free through Comcast's On Demand service.

DirecTV: Programs are downloaded to a hard drive in the customer's receiver box, via the satellite, and locked. When the viewer wants to see a show, the program is unlocked for 99 cents.