The iPad may still be weeks away from launch, but the companies that feed off the popularity of Apple Inc's products are already hard at work prepping for the new tablet.

The roughly 300 million iPods and iPhones sold over the past decade have given rise to a lucrative market for companies peddling a wide variety of accessories, including cases, adapters and docks.

These accessory makers have high hopes for the iPad, Apple's first major new product in three years, banking that it will become a blockbuster to help stimulate plateauing sales.

At the same time, thousands of application developers -- some large and some startups -- are looking to the iPad as a way to extend the reach of their games or services. Game publishers from Electronic Arts Inc to Tap Tap Revenge creator Tapulous have had good success selling games on the iPhone.

The iPad market has huge potential, said Jamie Elgie, a product management director at accessory company Belkin International. We think it has the potential to be game-changing and we need to be on top of it.

This week's Macworld Expo in San Francisco will attract thousands of Apple users and provide a showcase for third-party vendors for all of the company's products.

The 10-inch, touchscreen iPad has been the talk of the technology world since it was announced last month, and will likely be the center of attention at Macworld.

But because the iPad is a new category of device -- lodged between a smartphone and a laptop -- its form will present a unique challenge for highly competitive accessory makers.

Belkin and Griffin Technology, two top accessory companies, wasted little time in getting iPad sleeves up for sale up on the Web. Both say speed to market is important, given the low barriers to entry, and neither would divulge product plans.

The privately held companies say designing for the iPad will be tricky -- and neither will get a head start. They will not get hold of the device until consumers do, on launch day.

Apple itself will have some iPad accessories ready at launch in late March, including a $69 keyboard dock.

Mark Rowan, president of Griffin, said the iPad would be great, but exactly how consumers would use it was unclear. It will be a travel device, it could also be a home device, a family entertainment device.

Nashville, Tennessee-based Griffin makes the iTrip FM transmitter, among many other accessories.

Los Angeles-based Belkin, which makes iPod add-ons such as TuneBase, has annual sales that top $1 billion and roughly 1,400 employees. It holds more than 25 iPod and iPhone accessory patents.

The MP3 accessory market totaled $1.3 billion in the United States alone in 2009, according to NPD, although those in the industry say that estimate only captures a slice of the actual total, as it does not include retailers like Wal-Mart.

APPS

Macworld will have a special section dedicated just to apps, which Apple hopes will prove as popular on the iPad as they have been on the iPhone. There are more than 140,000 iPhone apps available, and almost all of them will work on the iPad. The devices share an operating system.

The iPad and its larger screen will provide a bigger canvas for apps, and many companies will overhaul their existing iPhone apps to look and run better on the iPad.

Brian Meehan, head of product development at software company and app developer Sourcebits, said the company has created a dedicated team of 80 developers to craft apps for the iPad. The company is based in Bangalore, India.

Sourcebits, which has developed apps for companies such as Coca-Cola and General Electric, saw its first iPad app inquiries arrive even before the formal launch.

We're working around the clock right now to handle the demand from our existing client base, and then on top of that, new clients are coming in to see what they can create around the iPad.

Games, which are already hugely popular on the iPhone, would seem to be one of the most obvious uses for the iPad.

The French mobile gaming company Gameloft has around 60 games available for the iPhone, which generate roughly 13 percent of its revenue.

Michel Guillemot, Gameloft's chief executive, said after the iPad launch that it will decide on a game-by-game basis which iPhone games it will redo for the iPad.

It's difficult to say what will happen. I think this device is going to bring a lot of user satisfaction, and what comes with user satisfaction is revenue.

Macworld organizers acknowledge it will have a different feel this year, with no headline-making presentation from Steve Jobs and no major product launches. Apple announced last year it would no longer exhibit or keynote at the show.

(Reporting by Gabriel Madway; Editing by Tim Dobbyn)

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