Some E-book sources: 

Free online reading material (ebooks) http://lib389.tripod.com/database.htm

 ALSC's Great Websites for Kids Committee

Bartleby.com: Great Books Online annoying ads(Classic Book Library –evidently defunct)

 Entertainment Software Rating Board good on e-games

International Children's Digital Library Gale Virtual Reference Books (fee based)

Greenwood eBooks for teenagers, fee based

Literature.org Novels in easy-to-read HTML format

ManyBooks.Net Well-organized site with multiple formats

OnLine Books Page thousands of texts

Open Library http://openlibrary.org/subjects/accessible_book  Multiple format options in most cases
Project Gutenberg large selection of free books

Questia wide selection, fee based

University of Virginia history oriented.  Many colleges now have similar e-book resources.

Victorian Literature

Gigantic Resource List for Resources in online print: http://drscavanaugh.org/ebooks/libraries/ebook_libraries.htm