In a nut: we're going to sell a ton of iPads.
iBooks 2.0 (or iBooks Textbooks)
A new version of iBooks for iPad and iPhone/iPod touch. On the iPad there's added support for interactive elements such as video and pinching/zooming on photos and other media elements. iBooks Textbooks is only available for iPad. The iPhone/iOS iBooks app got an update but Textbooks aren't included on the smaller devices. Free download.
iBooks Author
How to create the new books for iBooks? With iBooks Author. Your typical Apple app with nicely designed templates to start plus the ability for web nerds to author widgets and add ons with HTML5 and JavaScript. Drag a Word document right into it and have it auto-formatted. Drag a Keynote document right in to create a slide show in the book. Also a free download. Requires Lion (OS 10.7).
iTunes U
Previously iTunes U was only accessible via iTunes. Now available as a separate app for iPad and iPhone/iPod touch with a focus on helping teachers send out curriculum, syllabus, office hours, to-dos, etc. "Everything they need to do for a class." Obviously real world usage will dictate how well this actually works and you'll have to buy in (or convince your school's IT support nerd) to the Apple ecosystem to make it all work really well.
Read more about it at Macrumors.com or theverge.com.