This report is based on usability studies with real users, reporting how they actually used a broad variety of iPad apps as well as websites accessed on the iPad. If you are thinking of developing or deploying training to the iPad, this report would be useful.
Check it out: http://www.nngroup.com/reports/mobile/ipad/ ( 93 page report)
http://www.useit.com/alertbox/ipad.html (summary)