"Reading Teacher is a site that's been around for awhile. There used to be a cost involved, but just last week they made it free-of-charge.
It has one or two hundred online books for very beginning readers - sort of an expanded version of Starfall. Many of the books have short quizzes after them.
Though it's free to individual users, it does cost $20 if you want to create a virtual classroom of 29 students to track their progress.
I am using it, and will in the future, as another option for Beginning ELLs, particularly ones who have been out of school for a long time."