London - With the launch of Apple tablet PC impending, Amazon has launched an offensive in the e-reader market to increase the popularity of its already popular e-reader Kindle.

Amazon, whose Kindle e-reader controls 70 percent of the e-reader market, said it has released a software development kit (SDK) that will allow developers to build applications (apps), software and tools exclusively for Kindle users.

The kit, Amazon said, will comprise of sample code, ample documentation and, most importantly, a Kindle simulator that will allow developers to "build and test" their application in a virtual platform that mimics 6-inch Kindle and 9.7-inch Kindle DX in Mac, PC, and Linux environments.

The e-reader app store, the first of its kind, will be launched sometime later this year, Amazon said.

"We've heard from lots of developers over the past two years who are excited to build on top of Kindle," said Ian Freed, vice president of the Kindle division at Amazon. "The Kindle Development Kit opens many possibilities, and we look forward to being surprised by what developers invent."

Already many companies including Handmark and EA have come forward to develop apps and industry experts expect travel guides, RSS news readers and other text-based widgets to be key Kindle applications, while the range of games is expected to be extended from Sudoku to crosswords, puzzles or other logic games.

However, like Apple, Amazon said that the Kindle apps would need to be approved by them before appearing for download. Any app relating to "voice over IP functionality, advertising, offensive materials, collection of customer information without express customer knowledge and consent, or usage of the Amazon or Kindle brand in any way" will be rejected, the company said.

Amazon also has changed its royalty policy in favour of authors and publishers. Earlier, Amazon's pricing for books and media on the Kindle had courted controversy, with publishers unhappy at the online retailer's attempt to impose a flat $9.99 fee for books and taking a 65 percent of the cash, which leaves only 35 percent to the author and publisher. On the other hand, Apple's App Store offers coders 70 percent of the revenue, with Apple taking a 30 percent cut. So, not surprisingly, Amazon now has also decided to offer 70 percent of sales proceeds of e-books to authors and publishers provided they play by the rules.

Amazon also said that it is rolling out its Digital Text platform globally that will allow authors to self-publish their work and sell it through Amazon's Kindle store.

Anyone who uses the platform to sell a piece of work will receive 35 percent of the cover price, while Amazon takes the remaining 65 percent, and rights holders are in charge of setting the cover prices.

And, if rumour mills are to be believed, Amazon is also giving away Kindle for free to increase awareness of the device. Yes folks, it seems Amazon is emailing some of its customers, urging them to try Kindle. And, if it's not to their liking, they'll get their money back and keep the device for free!

Amazon's announcement comes barely days ahead of the expected launch of Apple's touchscreen-based iSlate tablet PC which, according to industry watchers, broadly resembles a large iPhone and will enable users to consume digital content, such as books, magazines and newspapers, on a full-colour, web-enabled device.

iSlate, it is rumoured, will boast of features like Intel 2.26GHz Core 2 Duo processor, 7.1-inch widescreen multitouch display, 120GB HDD and 2GB DDR3 SDRAM, apart from other bells and whistles like built-in projector, WiFi and Bluetooth.

And, unlike Kindle, whose monochrome, eInk screen and button-based interface make it unsuitable for many types of applications, Apple's tablet PC is expected to be able to play music, games and movies in addition to digital newspapers.

In other words, specs-wise, iSlate's better than Kindle any day.

No wonder, it seems Amazon's turning desperate. And, why not? After all, desperate times call for desperate measures.

However, many people feel that Amazon's move comes a moment too late. "If you are going to try to steal Apple's thunder just before its big Tablet announcement, you are going to have to do a little bit better than eInk Sudoku," wrote Erick Schonfeld at TechCrunch.com.

"Amazon is obviously concerned that the forthcoming Apple Tablet, which will be able to function as a lush, full-colour electronic reader for newspapers, books, and magazines might overshadow the black-and-white Kindle with its dot-matrix feel," Schonfeld said.

"But given the choice between developing beautiful, touch-screen, GPS-enabled, gyroscopic apps for an Apple Tablet and dorky eInk apps for the Kindle, developers are going to go with the Tablet first, is my bet," he added.