Apple ( long history of releasing a product and steering its industry. The Mac pushed the personal computer toward a graphical interface. The iPod widened the appeal of portable digital music players. And the iPhone raised the bar on handset features.

Now, Apple is poised to a release a new device a tablet computer but this time, the release could affect a wide array of portable consumer gadgets and the companies that make them.

The tablet, which is expected to be unveiled (and named) at a press conference Wednesday, could stir up competition because of its broad functionality. The device is expected to allow consumers to read books, magazines and newspapers; download music and videos; watch TV shows and movies; and perform other functions previously limited to desktops, laptops or netbooks.

Physically, the tablet is said to include a 10-inch color display, a wireless Internet connection over 3G and Wi-Fi networks, and the ability to run most of the applications on the iPhone and iPod Touch.

What could a machine like that do to the marketplace? The tablet will be about transforming the market for the consumption of newspapers, magazines, books and films very much bringing that rich content on to the portable market, says James Cordwell, a digital analyst who covers Apple at Atlantic Equities, an independent equity research firm.

Here are seven companies and sectors that Apple s tablet is likely to impact.

Apple

Apple products have been unique in their combination of sophisticated hardware, unique user interface and access to a media ecosystem, like iTunes, which allows consumers to buy songs, movies and TV shows. Consumers can expect more of the same from the tablet.

However, this time around, Apple will face a new challenge. Magazines and television two media the tablet is said to display have existing distribution mechanisms and powerful players, says Cordwell.

The tablet could also create new competition among other Apple products. Cordwell says that it s unlikely, based on the company s historical performance and that revenues for the iPhone and iPod grow each year. When they come out with a new product, it makes the brand more popular, he says. And when people buy one Apple product, chances are they ll buy more, so the overall cake is getting bigger [for Apple] rather than cannibalization ensuing.

One exception could be the Macbook. If the tablet is in a similar price range, some say consumers would likely choose one or the other. It s going to be very difficult for Apple to convince consumers that they need an iPod, iPhone, Mac and tablet, so some will chose one over another and that could lead to some cannibalization of sales, says Bill Kreher, a senior technology analyst at Edward Jones.

In the short term, investors shouldn t expect huge sales. People who will buy this off the bat are Apple diehards, says Toan Tran, associate director of technology research who covers Apple at Morningstar. But as the tablet s price declines over time, it could grow more popular. Apple hasn t announced a price yet, but analysts interviewed for this story estimate it at between $500 and $1,000.

In the long term, the tablet could be a boon to Apple shareholders. It s part of Apple s strategy to be at the center of everyone s digital lifestyle, says Tran who says the stock is fairly valued and that opportunities exist for expansion among existing models. For example, Macintosh makes up around 8% of U.S. PC business and 3% global, he says. Also, 12 million iPhone units sold in 2009, compared with one billion mobile phones that sold globally.

Investors should also consider what will likely be fairly low operating costs for the tablet. Content for the device will come from a host of providers, which may include book publishers and music labels, says Jeff Orr, senior analyst for mobile devices at ABI Research. As a result, the company has less engineering and research and development overhead than is typical when creating a new consumer product.

Either book publishers or large book stores like Barnes & Noble or Borders are likely to benefit from the release of the tablet.

If Apple partners with [a book store] that provides content for the tablet, it could be a positive, says Cordwell. But if Apple goes straight to the book publishers and sells books directly through the iTunes store, it s cutting out book stores.

In addition, the tablet may create competition for Amazon.com Kindle, which could be more favorable for book publishers, he says. Meanwhile, book stores are pinning hopes on digital distribution as a way to offset declining sales and revenues.

E-Readers

The tablet is likely to stir up competition and snatch up market share from a host of e-readers made by companies like Sony, Barnes and Noble and Amazon, says Clyde Montevirgen, an equity analyst who covers Apple at Standard & Poor s.

Apple s strength will be in its hardware, while the Kindle s strength lays in its vast availability of books and Amazon s retail experience. Still, for the most part, the Kindle is a single-purpose device for reading; consumers in the market for an e-reader may look to the tablet as an alternative because it also offers additional entertainment and computing options, says Tran.

However, consumers shouldn t be surprised if Amazon fights back with a new, updated Kindle. Cordwell expects a new Kindle to be announced in the next six months.

Cable TV Providers

Rumors are circulating that, eventually, some type of subscription television service will be offered to tablet users, allowing them to watch TV shows on the device. Cable television is one of the larger challengers the tablet will face, says Cordwell. Cable TV is a very lucrative distribution channel for TV content providers, so getting them to come to the table and negotiate rights to some form of a subscription package will be hard, he says.

ITunes now sells TV shows and movies, so one question is what route Apple will use to provide the TV element. If that distribution channel is successful, cable providers like Comcast, Time Warner and Verizon could face a looming threat in the long term.

If you look at what Apple did to the music industry before you had to buy a whole CD and now you can buy songs a la carte, Montevirgen says. A similar approach to television shows wherein consumers could purchase only the shows they want to watch, rather than be forced to buy an entire cable package could shake up cable companies.

And it s likely that the tablet will connect to TVs for a better viewing experience.

The tablet will offer most of the features now available on netbooks, but analysts say netbook sales should remain strong going forward because of their price point.

Netbooks are priced at around $300 each, says Tran, a much lower price point than the tablet s expected one. Also, the tablet s computing capabilities may be inferior to those of netbooks because the device is not expected to include a traditional keyboard. If anything, [the tablet] will propel netbooks further because it will give customers the opportunity to compare the two, says Orr.

Newspapers and magazines

These industries are facing similar revenue pressures as books are, and most analysts agree they ll be impacted by the tablet.

The tablet could increase revenues for newspapers and magazines because it would likely charge users to view those media, essentially recreating a platform in which readers would pay for the content rather than consuming it free, says Cordwell.

For both parties to be profitable, the publishers would have to get about half of the revenues, says Montevirgen. News reports suggest that companies will charge for their content and that publishers, including Hearst and Time, are creating mockups of their magazines for tablets. (SmartMoney is joint venture between Hearst and Dow Jones.)

Competing tablet makers

The tablet design has existed for about a decade, but the existing products represent less than 1% of all PCs sold, says Kreher.

The tablets already released by companies including Hewlett-Packard, Lenovo and Always Innovating are likely to face competition from Apple s device, given its current hype and the expected functionality.