I surfed Project Gutenberg. Preliminarily it seems like they have a lot of old books that aren't copyrighted in the US--Austen, Twain, Dumas, etc. It's very easy to use. I opened a PDF version of Jane Austen's Emma and read a few pages of its total 361.
I also opened a HTML-version of Mother Goose; it was wonderful because it had illustrations for many of the sayings and you could click their titles in the table of contents to immediately go to them.
One big difference between netlibrary.com and Project Gutenberg is that netlibrary.com has all the latest fiction and nonfiction titles printed in recent years for one to listen to.
All of these resources would be great if someone wanted to immediately read a particular book, but all the copies were checked out. But it does take getting used to reading a whole book on the computer or listening to one read to you.