Lefty and Ron (now remade for iBooks with more animation and interactivity) is an illustrated children's story that can read itself aloud. It's the tale of two socks who get wet and dirty, are stretched around a leg, have a wash in a twisty-turny barrel, dry on a washing line and even get lost in a dark corner.
Suitable for pre-school children and those learning to read, the application uses a simple user interface that's easy to use for children of any age. Free, without ads, and with a couple of interactive surprises.
Read to your child, let them read on their own, or tap the text and it will be read out loud by the author.