I don't have any kids (yet), but if I did I'd be all over Children's books for Windows Phone. It's a free app in the Windows Phone Store for youngsters and parents of said youngsters. WIth it you get interactive books for kids, a coloring book and a memory game. Scroll down for a hands-on video of the app.
Children's books for Windows Phone is a free app and definitely one worth downloading if you have small kids. Right now you only get one book, which is a bit of a bummer. I'd love to see this app updated with more books, which are teased right next to the book you do have access too. Of course it's not hard to imagine future books being purchased through in-app purchases.
One feature I know a lot of kids will love is the ability for parents to record their own narrations. The books can be read by a default narrator, but why not let a familiar and loved voice read to you? It's a great feature and hopefully one we'll see in future books.
Highlighy recommended app for kids and parents with kids. It can only get better once more books are added. Download Children's books for Windows Phone and let us know what you (and your kids) think!