Many people have worked hard to get classical books onto the internet, so they will be available to as many people as possible. These are books that are in the public domain. "Public domain" means that a book is past its copyright (usually published in the early 1900's and before).
Librivox provides books that are read orally by readers for your - or your child's - listening pleasure. If your computer is equipped to read an MP3 file, you can simply click and read. Alternatively, if you wish, you can download a file onto your hard drive.
If you would like for your student to read the text on the computer, or if you want to print materials for him or her, you may also like the more plentiful options available at byGosh.com. This site provides: Kid's Classics, Short Stories, Novels, Nonfiction, and Poems.
Another resource I would like to share is the Gutenberg Project. These are files that you download onto your computer. I haven't tried them yet, as I had an overloaded computer until very recently; so I got used to using only things that we could just "click and read"; but the advantage here is the scope. The Gutenberg Project has 20,000 free books available. If you like the Gutenberg Project, you may like some of the curriculum ideas from Miss Maggie at her Old Fashioned Education website.
Another resource where downloading is required is AudioBooksforFree.com. At this site, they will be happy to sell you downloads to your MP3 or other personal player; however, they also offer free downloads to your computer.
I hope something here will be helpful to you!