Interesting changes coming from Apple on how iDevices can be used in education... read up here!
http://www.redorbit.com/news/technology/1112914999/apple-ids-for-students-to-be-allowed-with-consent-080413/
Also, TeachMe Toddler is free today (August 5th)... great for preschool and K and struggling students. Works on alphabet and numeral recognition, shapes, counting...