Here are some of my favorites:
- Unite for Literacy: The vision of this site is "picture book abundance". The original digital books on this site can be narrated in many languages. The books are mostly simple nonfiction with leveled text.
- International Children's Digital Library: A project originally started by IMLS and the National Science Foundation. It is geared towards ages 3-13 and includes 4642 books in 61 languages. I like that you can search for books by country, and will definitely be keeping this site in mind as a source for books in non-English languages.
- We Give Books: eBooks read on this site help provide book donations for needy children. To read books you must create a free account.
- Free Kids Books: Kids can read books online at this site or download them as a pdf. I really like that you can limit your search by age.
- Between the Lions: Animated books are broken down into categories, such as "Folktales and Fables". The text in each story highlights the words being read, which is important for developing word recognition skills and concepts of print.
- Eduplace Leveled Books: A small selection of leveled online books. For each book it lists the reading level and skills covered. It also provides a few support resources for teachers.