The bummer about some of the subscriptions MMSD purchased is they are flash based and do not work with the IPad. One of the reasons we purchased TumbleBooks was they are in the process of converting their books into an IPad friendly format.
The IPad friendly books do not have the same interaction as the flash based books. The IPad books are in a movie format so there is no page turning. Students just watch and listen to the book without needing to turn the page. This could be a plus in a literacy center setup.
The first thing you need to do is open a the web browser and go to Links 4 Kids. http://tinyurl.com/scharks Next you will click on TumbleBooks and look for the IPad Books. All of the books you see are compatible with the IPad.