Amazon Kindle is right now just known as the handy ebook reader. However, to compete with Sony and now Barnes & Noble, Amazon is also planning to launch software versions of Kindle that would allow users to download and read ebooks on their computers.
Initially, with the Windows 7 launch, Microsoft hinted about a Windows version of the software coming soon and now Amazon is announcing that a Mac version is on its way as well. This is an effort by Amazon to make Kindle compatible with more and more platforms to acquire more market share. Amazon Kindle already has a compatible version for iPhone/iPod Touch.
There is no estimated shipping date for the software yet. However, an interesting point is that release of Apple Tablet would put Apple in direct competition with Amazon due to its small size and portability.