iTunes U is a hosted content management system that provides a way for colleges and universities to make both audio and video content from lectures, interviews, audio books and more available to students online. Released in 2007 by Apple, it was only on Tuesday, March 30, 2010 that Apple applied for the mark ITUNES U trademark with the description, Online retail store services featuring pre-recorded audio and audiovisual content among others.
As recent as 23rd March Harvard University signed up and made its presence felt on the iTunes U. For the majority of people, iTunes U is only going to be relevant if their school utilizes it. A huge number of schools have signed on to iTunes U since its start in 2007, but they remain a fairly small fraction out of the world.
If your class specifically has iTunes U content they will have to instruct you to find it as this is not the way that it is set up. Also another drawback is that the iTunes U content can begin to pile up very quickly, especially if you are using it for your classes. This means that you are going to constantly have to clear out the excess from your iPhone or iPod Touch.