iTunes U is a free app from Apple and a whole eLearning platform. The "U" means, of course, University but according to the company "it’s easier than ever to unleash the full potential of iPad in your classroom by creating your own courses for iPad".
More over, you get to share your ideas in a powerful new way, and your students get a rich, immersive learning experience using the iTunes U app for iPad. iTunes U is available no matter where you teach — at any college, university, or K-12 school.
With this Platform+App integration you can organize your courses in a Library, offer a complete Syllabus and the whole kind of necessary resources for a succesful online course using an iDevice (iPad, iPhone) as you can see here:
https://www.icloud.com/photostream/en-us/#A2JtdOXmG5GgFNThis slide show was generated by sharing an iPad Photo Stream on iOS 6, a very useful and super fast way to share pictures.
Warm regards.