International Children's Digital Library
http://www.icdlbooks.org/
Children's books from around the world - choose the language, age level and type of book you want to read.

Big Universe
http://www.biguniverse.com/
For ages 5 - 11. A picture book site of fiction and non-fiction titles categorized by age level and theme, add your favorite titles to a virtual bookshelf. Create your own books on this site as well--they provide the images and cute animations!

Lookybook
http://www.lookybook.com/
Over 300 complete picture books that you can look at and read online. Search the site to find many new and interesting titles.