Jan Brett has a set of sight or Dolch words (the 220 most frequently found words in the English language) with fun illustrations from her books which you can printout as flash cards or pages at http://www.janbrett.com/games/jan_brett_dolch_word_list_main.htm
The Magic Tree House books have a website that offers worksheets and more for teachers at http://www.randomhouse.com/kids/magictreehouse/
Book Adventure: http://www.bookadventure.com/ You sign your kids up, and they read books from the book list. You can search the database for books by reading level and by
interests. When they have completed the book, they take a short quiz on the book to check their comprehension and they earn points for each book they read. They can earn prizes with the points they get. There are certificates for free books with Amazon.com, learning software, magazine subscriptions, temporary tattoos and more. It's a free program sponsored by Sylvan Learning Centers. They also offer an email progress report for parents. If the kids are doing it on their own, but the prizes are not sent unless the parents approve of the prize the child has selected.