Having to launch the iTunes client to browse iTunes and iTunesU client is often one step too far for me – as soon as the request to launch iTunes appears, I cancel the request – so I put out a quick call to see if anyone knew of any online, web based, HTML front ends to iTunes and iTunesU, and here’s what turned up.
From @liamgh, iTunesU in a browser:
(The UI of the higher levels of this site isn’t quite so pretty, though…)
Clicking on the view link allows you to watch the content in the browser:
Via a tweet from @sboneham, I also got a link to an iTunes and appstore app on Google apps (the iTunesU link requires the iTunes client…maybe these folks should talk?) App Store:
As far as machine access and APIs go, here’s a Java API to iTunesU.
OUseful.Info, the blog... 
Here are the details for iTunesU in a browser:
http://www.fritscher.ch/blog/2009/05/13/browsing-itunesu-without-intalling-itunes/ Interesting technique and goes some way to bringing content in iTunesU to us Linux users, if it isn’t already available in a normal podcast site.
All apple has to do is can that bit in the preview page that auto launches itunes. There is a freaking button there “open in iTunes”.
Their present approach spits in the face of the human interface design guidelines.