Here are a few of my favorites that I ran across:
I use this one to teach point of view.
Another great website for digital books is www.wegivebooks.org There are tons of both fiction and nonfiction books on this site and they are FREE! The books are not read aloud, but I have projected them on the board or had students read them at our classroom computers. There are a lot of nonfiction books about animals that could be used for research projects. You could also project the nonfiction ones on the board to discuss text features. One more idea...you could use a screen recorder to record yourself reading one of the books from the website. Then, students could listen and read along. If you have Promethean ActivInspire, just use the video recorder to do this (see a tutorial on how to do this here).