Amazon threw down the gauntlet against terrestrial competitors today by announcing that Kindle and Kindle app customers can borrow and purchase Kindle books from more than 11,000 local libraries in the United States.

In essence, these first 11,000 local libraries just became a chain of local bookstores for Amazon's catalog of virtual books.

The move will create a twist in the already highly competitive book-selling landscape, pitting the Kindle against devices like the Nook, which allows users to download books, for a fee, when they visit their local bookstore.

It's an extension of the lending library idea we wrote about earlier.

Kindle users will be able to sync a borrowed book's margin notes with Facebook or Twitter for a little literary graffiti.

"Normally, making margin notes in library books is a big no-no," says Jay Marine, director, Amazon Kindle. "But we're fixing this by extending our Whispersync technology to library books, so your notes, highlights and bookmarks are always backed up and available the next time you check out the book or if you decide to buy the book."

Customers use a local library's website to search for and select a book to borrow. Once they choose a book, customers can choose to "Send to Kindle" and will be redirected to Amazon.com to login to their Amazon.com account and the book will be delivered to the device they select via Wi-Fi, or can be transferred via USB, the company said in an announcement.

Customers can check out a Kindle book from their local library and start reading on any generation Kindle device or free Kindle app for Android, iPad, iPod touch, iPhone, PC, Mac, BlackBerry or Windows Phone, as well as in their web browser with Kindle Cloud Reader.

To start checking out Kindle library books, device owners can visit their local library's website, or for more information, they can visit a page Amazon has set up for library lending.