Kindle for PC is a free application that lets you read Kindle books on your PC.

Read Kindle Books on Your Computer

• Get the best reading experience available on your PC. No Kindle required.
• Access your Kindle books even if you don't have your Kindle with you.
• Automatically synchronizes your last page read and annotations between devices with Whispersync.
• Create bookmarks and view the annotations you created on your Kindle.