Mercer Mayer's Little Critter has been entertaining tots (and teaching them about new things) for several generations now. So when it comes to potty training, it's no surprise that parents and kids love to turn to their favorite character. The New Potty — Little Critter app ($2) is the story of a little sister learning how to use the potty (complete with lessons about accidents and fear of being normal) as told through her big brother. Mom and dad can record their voices reading the text or a narrator can be used, in addition to tots reading it on their own. The app is a great companion to other training efforts.