By Neil McManus

Cable television executives have been promising video-on-demand for years. Somebody should tell them it is already here.

The other night I hooked audio-video cables from my PC to my television. Then my wife, Emily, and I sat on our sofa and watched full-screen, full-motion videos through our broadband Internet connection. Although far from DVD quality, they looked and sounded as if we were watching regular old television.

Why get video through the Internet when you have hundreds of channels on cable or satellite TV? One reason is the difference between a lot of choices and a staggering number of choices.

Consider our night of online viewing: On Cinemanow (www.cinemanow.com), we saw the so-bad-it's-good horror movie "Leprechaun," which is usually relegated to the wee hours of TV. On Intertainer (www.intertainer.tv), we watched a music video from the Mexican rock group Café Tacuba, which you will never find on MTV. The Molly Ringwald sitcom "Townies" lives online at Yahoo Broadcast (broadcast.yahoo .com) even though ABC canceled it in 1996 after only half a season. And the video shorts we watched on iFilm (www.ifilm.com) were made for the Internet by hobbyists with camcorders and video-editing software.

Hooking our new Compaq PC to our 10-year-old television set took some work, but it turned viewing Net videos into a social experience. You don't need to take this step to watch video full-screen on your PC monitor, but you will need a relatively powerful PC. Intertainer, for example, requires a PC with Windows 98 or later, the Internet Explorer browser, a 400-megahertz processor, 64 megabytes of RAM and a broadband Internet connection. Most video-on-demand sites also support newer-model Macs as long as they have the latest Web browsers and the latest version of RealPlayer, QuickTime or Windows Media Player.

The videos at the sites we visit — music videos, shorts, television shows and vintage movies — are not pirated, but most are free. (Yahoo Broadcast and iFilm, however, will make you sit through commercials before you view a video.) To watch recent motion pictures, concerts and sporting events, you will either pay a monthly subscription fee ($8 to $10) or pay as you go (typically $2.99 or $3.99 for a 24-hour rental).

To some, all this may seem like taking a vast wasteland to new extremes. But for video devotees, it is a glimpse of a promised land where you have the ultimate in control over what you watch at any moment.

On Intertainer, I can watch the 1974 title fight between Muhammad Ali and George Foreman, the Rumble in the Jungle. Pausing it with a click of the mouse, I can go to MovieFlix.com (www.movieflix.com) and choose a "Dragnet" episode. Or switch over to Burly Bear Network (www.burlybear.com) for my favorite Chicken Lady sketch from the comedy troupe Kids in the Hall.

This do-it-yourself video-on-demand experience is something like using TiVo's personal video recorders, which let viewers pause and resume playing TV programs even as they are being transmitted and recorded.

The video quality, however, is not as nice as TiVo's. (If your cable or D.S.L. connection slows down, the streaming video available over the Web may look grainy and even come to a halt while the media-player software restores the connection — a phenomenon known as buffering.) And a bigger difference is that you are not recording; your PC is using a broadband connection to play digitized videos that somebody else has put on the Web, and you are watching them remotely.

If you are venturing into the world of Web video for the first time, a good place to start is iFilm, an addictive site that assembles entire movies, TV episodes, comedy sketches, spoofs and music videos. The iFilm site is best known for inventive made-for-the-Web video shorts, like "405: The Movie," in which a driver frantically tries to get out of the way of a jetliner making an emergency landing on a freeway. The site makes it easy to send links to video clips by e-mail and encourages viewers to post comments and rate the video.

Over at Yahoo Broadcast, you can watch an eclectic mix of streaming videos including celebrity interviews, television shows, movie trailers, music concerts and instructional and travel videos. Yahoo showcases videos culled from lesser-known sites like Wild Brain and Classicmovies.com.

Yahoo also has a handful of full episodes from the sitcom "Townies," "The Andy Griffith Show" and other programs. If you are eager to step into a TV time capsule, LikeTelevision (www.liketelevision.com) offers hundreds of full episodes of long-canceled shows like "The Beverly Hillbillies," "Bonanza," "Dragnet" and "Alfred Hitchcock Presents."

As for full-length feature films, CinemaNow offers about 150 movies free — many of them B-movies, like "Killer Klowns From Outer Space" and "The Wolves," though you will also find classic films, like "The Kid" with Charlie Chaplin, as well as Hong Kong action movies, including "No Sir" and "Oh Yes Sir."

CinemaNow also rents movies for online viewing. For $1.99, you can watch "The Toxic Avenger," starring a hideously deformed creature with superhuman strength. For $2.99, you can watch "Double Down," starring Jason Priestley. The site offers an unlimited monthly pass to its premium films for $9.95.

As it happens, Cinema Now's investors include Blockbuster — an intriguing association, since video stores could lose out if pay-per-view movies through the Internet catch on, as could cable and satellite-television providers.

The movie industry has a more fundamental reason to want to tame the medium: to pre-empt the online pirating of movies that Napster made possible on a viral scale with music. The president of the Motion Picture Association of America, Jack Valenti, told Congress in April that an estimated 350,000 movies were being downloaded "illegitimately" every day.

At the same time, though, the studios clearly see the Web as a potentially lucrative new means of distribution. Intertainer is the first Web site to show movies in what the film industry calls the "first-run pay-per-view window." Last month it was renting "Angel Eyes," "Cats and Dogs" and "Swordfish" at the same time cable pay-per-view channels were. Intertainer charges $7.99 a month for its basic programming service, which includes TV shows, concerts and sports, plus pay-per-view fees of $2.99 to $3.99 a movie.

This year Intertainer may get competition. A coming pay-per-view site, Moviefly, is being backed by such Hollywood studios as Sony Pictures, MGM, Paramount Pictures, Universal Studios and Warner Brothers.

The Walt Disney Company and 20th Century Fox have not yet agreed to distribute films through Moviefly — perhaps because Disney and Fox are planning a competitive Internet video-on-demand service through Movies.com (www.movies.com).

As studios, cable and satellite companies and video stores continue to duke it out, the battles over what to watch at our house no longer center on the remote control. They are now fights for the mouse.