Amazon.com today announced a free version of its Kindle reader software for Windows PCs, a big step toward Jeff Bezos' goal of getting the software on all sorts of devices.

With the mini-bookstore loaded on your computer, you can buy Kindle versions of books from Amazon and access your Kindle collection from the Web. The software also keeps track of how far you've read and synchronizes your progress with your various Kindle devices.

There's also a feature that may be of interest to business and education Kindle users. Annotations and bookmarks created on a Kindle can be viewed on a PC directly through the application.

The app also supports touch gestures on Windows 7 systems with touchscreen hardware. Users can "pinch" with fingers to zoom in and out of text and turn pages by swiping a finger across the screen.

A Mac version is "coming soon." The company earlier released a version for the iPhone.

PC users don't need a strong machine to download and run the software. Here are the minimum system requirements:

-- A PC with a 500MHz Intel or AMD processor or faster.
-- At least 128MB of RAM.
-- Screen resolution of 800 x 600 or greater.
-- Windows XP Service Pack 2 or later, or Windows Vista or Windows 7.
-- 100 MB of available disk space.