New iTunes U app delivers online courses to mobile devices.: 
The new iTunes U app allows educators at universities, colleges, and K-12 schools to design and deliver full courses directly to your iPhone, iPad, and iPod touch. Free to everyone, the courses cover everything from astronomy to business skills to the knife skills of a professional chef and more. In addition to access to the more than 500,000 free lectures, videos, books, and other resources already available via iTunes U in the iTunes Store, the iTunes U app supports new features that let you view the course assignment list, track your progress, make notes as you go, see notes and highlights from linked materials, and see the complete list of materials the instructor is using or recommends. For good examples of courses that include support for these enhanced features, get a free subscription to American Revolution from Yale, iPad and iPhone App Development (Fall 2011) from Stanford, Open University's Communicating Through Music, or Core Concepts in Chemistry from Duke.
The iTunes U app keeps a library of the courses you subscribe to just as iBooks keeps a library of the books you buy. To navigate between the catalog and your courses, use the buttons on the top left on iPad and the top right on iPhone and iPod touch. In your course library the covers for courses that support the new features display a spiral binding on the left. Use the tabs on the right on iPad or the buttons across the bottom on iPhone and iPod touch to explore the assignments (Posts) and the note taking capability and materials lists.