In what may be a response to Apple's rumored tablet device, Amazon is opening up its Kindle ebook reader to third-party developers. Amazon plans to roll out a limited beta of its Developer program in February, and is calling Kindle applications "active content."

The Kindle developer program will include the Kindle Development Kit, or KDK, developer support, sample code, documentation, and a software-based Kindle simulator for Mac, windows and Linux. Amazon will support free, one-time purchase and monthly subscription options for active content.

Until now, the Kindle was off limits to developers, but that could be changing thanks to the real possibility that Apple will introduce its own tablet device at its special media event on January 27. Apple's rumored tablet device is said to offer ebook reader support and support for third party applications much like the iPhone and iPod touch.

Amazon also announced this week it is changing the payment structure for ebook sales. The new payment setup matches Apple's 70-30 App Store split, and Amazon will use the same payment scheme for active content, too.

Even if Apple doesn't introduce a tablet device next week -- and at this point that seems unlikely -- the company has already forced changes on the rest of the industry, which ultimately could translate into more options for consumers.