Holy shit. Watch out Amazon, here they come!
Google's mission is to organize the world's information and make it universally accessible and useful. Since a lot of the world's information isn't yet online, we're helping to get it there. Google Print puts the content of books where you can find it most easily; right in Google search results.
To use Google Print, just do searches on Google as you normally would. Whenever a book contains content that matches your search terms, we'll show links to that book in your search results. Click on the book title and you'll go to a "content page," where you can see the page containing your search terms and other information about the book. You can also search for other topics within the book. Click on the "Buy this Book" link and you'll go straight to a bookstore selling the book online.
If you're a book publisher and you'd like to have your books included in Google search results, look into the Google Print program for publishers.
UPDATE: It appears that people have known about this since last year and it has been on and off in test mode, but the official announcement was Oct 6th.