SAN FRANCISCO — What Apple Computer Inc. did for music, it now hopes to do with movies.

The company whose iPods revolutionized the way the world listens to music on Tuesday started selling downloadable movies — about $13 to $15 for new ones, $10 for older titles — for computers and iPods, and said future flicks will be available on its iTunes Web site the same day they are released on DVDs.

Even more significantly, Apple gave a sneak peek at something it calls iTV, a device the size of a few slices of toast that's designed to wirelessly beam downloaded movies, music, home videos and pictures to television sets and computers scattered throughout a home. It plans to introduce the product early next year at a price of $299.

If it's successful, iTV could reshape home entertainment for consumers and have a powerful effect on a wide range of businesses, including the computer industry, Hollywood, cable TV and video rental companies.

"This is the missing piece," Apple co-founder and Chairman Steve Jobs said as he balanced a prototype in the palm of one hand at a press conference in San Francisco. "Here it is."

If iTV takes off, Jobs said, Apple will be in consumers' dens and home offices with PCs, in their pockets with iPods, in their cars with iPod-equipped automotive stereos and in their living rooms with iTV.

Disney CEO Bob Iger, who joined Jobs at a presentation, called Apple's latest foray just as transformational as when it started selling downloads of TV shows.

"We're here today to take the next step in the natural progression in moving media from traditional platforms to new platforms," he said.

But the company still faces significant hurdles.

Entertainment and technology companies have been trying for years to figure out how to deliver movies over the Internet, with limited success. Apple archrival Microsoft Corp. introduced its own media hub, Windows Media Center, several years ago, but so far has had a lackluster reception from consumers faced with the prospect of replacing their DVD players, TiVo recorders and stereos with a computer.

Moreover, just because music worked on the Internet, it doesn't mean movies will. Movie files are immensely bigger than music files. Transferring them wirelessly is particularly hard.

Meanwhile — unlike the music industry in the early days of digital music — traditional home entertainment companies like cable and satellite providers have plans for video on demand and other services that are already well under way. One of them is Cox Communications, one of the nation's biggest cable companies and a sister company to Cox Newspapers.

"I don't think this is a slam dunk by any stretch of the imagination," said David Card, an analyst with technology research firm Jupiter Research. Unlike with digital music, Card said, "we don't necessarily need Apple to show us the way this time."

Card said that traditional cable and satellite companies can deliver movies more quickly through networks that are much more secure and efficient than the Internet. DVD purveyors such as Blockbuster and Netflix, he added, probably aren't going away soon either.

Indeed, even with the fastest home Internet connection available, Jobs said it can take about 30 minutes to download a full-length movie on iTunes.

That said, Apple's planned expansion into the living room can't be discounted, given its success with iPod and iTunes. Jobs said Tuesday that the company now has a commanding 76 percent market share for digital music players and an 88 percent share of the market for legal music downloads.

Building on that success, Jobs also unveiled a new lineup of iPods with brighter screens, more storage space and longer battery life that are designed for watching movies and other video. For people who just want music, he also introduced a tiny $79 clip-on iPod Shuffle that's about the size of a matchbook and can hold 240 songs.

Apple also announced that it would begin selling iPod games such as Tetris and Bejeweled on iTunes for $4.99 each.

But it is the movie announcements that are most likely to make major waves in the entertainment world.

Jeff Kagan, an independent technology analyst in Atlanta, said consumers are increasingly faced with more choices of where to get their entertainment. Apple, he said, has a proven track record of making devices simple and easy to use and understand.

"The television business as we know it is changing," said Kagan. "What you're going to be able to do is watch anything you want anytime you want, anywhere you want. And Apple wants to be a part of that."

As it turns its sights to the television and movies, Apple has a formidable partner in the business.

The first 75 movies available on iTunes will come from Walt Disney Co. and its five studios. They include top hits such as "Pirates of the Caribbean" and "Cars."

Disney, which owns ABC and ESPN television networks, was the first company to make its shows available on iTunes. Since then, 40 other networks have reached agreements with Apple, and Apple customers have downloaded more than 45 million shows, according to Jobs.

The association with Disney is no coincidence. Disney earlier this year bought Pixar Animation Studios Inc., which Jobs previously owned. Jobs became Disney's biggest shareholder through the deal.