At WWDC this year Apple introduced a new category 'Kids' in it's app store. Now developers can also narrow down what the target age of their app is for.
The following age ranges are available:
Ages 5 & under
Ages 6–8
Ages 9–11
You can only choose one age range for each app. Apps approved for the Kids category will still have a primary and secondary category, but will also appear in a new, separate area of the App Store. To assign the Kids category to an already existing app, submit a new version of your app for review. Starting this fall, the currently existing Kids subcategory for game apps will no longer be displayed on the App Store.