Children's Spanish Books for the Kindle

If you have a digital device like an ipad or smartphone you can download this chapter book (Un príncipe en la nevera) for free.  I'm not sure how long it will last so it might be a good idea to grab it while you can.  It looks like a cute book and it has an average of 4.25 stars out of the 29 reviews on Amazon.

This book would be best for kids with a high level of Spanish.  I could easily see doing some sort of project with a short chapter book like this in Spanish IV.

Do you use digital books with your kids or students?