iTunes U for K12
The K12 news could be more of a motivator for change than the textbooks in the K12 space. I can see some teachers creating textbooks, but creating podcasts and support materials for iTunes U will be much easier. In fact, many educators may already have some of those materials created and ready to upload.
Of course, K12 is very different than higher ed - especially when it comes to issues like permissions for using students and student work and the probable "review process" that will be required by a school district.
To get started with iTunes U, K12 school districts, universities, and colleges in 26 countries can start at eduapp.apple.com