Gordon, here's the other sites I like to check out. A couple are free, but one or two have titles which are more expensive than at the Sony store. Also, at the very top of this page, next to Home, click on Forums. Scroll down til you reach Deals, Freebies, and Resources. I have found a couple of the following sites there. Here's my little list for what it's worth-
www.feedbooks.com
http://manybooks.net
www.gutenberg.org
www.free-ebooks.net
www.ebooks.com
www.booksonboard.com
www.smashswords.com
www.stevejordanbooks.com
Hope this helps. Can anyone add to my humble list?