Amazon is doing very well with its Kindle eReader and the device is one of the most popular readers on the market. Amazon is being forced to up the pricing of the digital books that go along with the reader, thanks in large part to Apple.

Amazon announced a while back that it was launched a new Kindle Developers Program that would allow devs to build active content for the reader. Amazon announced recently that the KDK program was now rolling in limited beta and offered a few more details on the active content the program will produce.

Three pricing options for the content developed with the KDK will be available. The free option requires the app to be under 1MB in size and use under 100KB/user/month of wireless data. A one-time purchase plan will be for apps with data use of no more than 100KB/user/month. A monthly subscription plan will be used for apps that use more data. The largest app size allowed is 100MB and apps larger than 10MB will only be available to upload via USB.