There was a time when iTunes U was just a section of the iTunes store where you could download audio and videos. Since Apple’s recent education event, that’s all changed. iTunes U is still a part of the iTunes Store but there’s now a dedicated iTunes U app for iOS devices.
The other major change to iTunes U was a policy change. iTunes U was previously only available to universities. At the January education event Eddy Cue stated that “starting today K-12 schools can sign up” to iTunes U. We didn’t get pre-announcement access but I signed up as soon as I could and Cedars has been accepted to iTunes U.