iBooks Author generates ePub, and you can even use other reading systems (except for apple-specific things). However the license agreement prohibits you from selling content that iBA generates anywhere except for iBookstore. Can you believe that?
http://www.pigsgourdsandwikis.com/20...t-you-can.html
To me this all looks like a way to force students to buy iPads and Macs. I don't see any benefit to students. Surely they will still have to purchase regular textbooks for many of their classes.