Hi, Mona, there are definitely plenty of sites for books for Kindle. If you like science fiction, stop by Baen Books (
http://www.baen.com), they have a selection of low-cost and free ebooks. I highly recommend the books posted here--forum members edit them and my experience so far is that they are of a high quality with fewer typos than one often finds in public-domain works. You can load the directory of available books on your Kindle and then download them directly. Manybooks (
http://manybooks.net) and Feedbooks (
http://feedbooks.com) also have free ebooks for Kindle.