Amazon has released its latest version of the Kindle Reader and Bookstore today on the Windows 8 platform.
This is a fully featured application that allows you to buy and read books within the singular program.
Once installed you sign in with your Amazon account and all your books are listed under the Cloud view and then if you start reading a book it automatically downloads the whole book.
The books are synced up with Whispersync and you can add bookmarks and notes to the books.
If you are interested in downloading it, you can search for Kindle in the Windows App store.