Gilbert Sewall, director of the American Textbook Council in New York City, wrote a compelling opinion piece in Education Week that I agree with:
Portable readers and on-screen classroom lessons are on the horizon. But printed textbooks will not disappear tomorrow. Hardbound books still dominate the $7 billion textbook market. Digital textbooks make up less than 5 percent of sales, and that includes textbooks at the college level, where for many reasons e-texts make more sense than in schools.
Even in an electronic age, books remain, when compared with plug-in and battery-operated laptops, cheap, portable, and durable. They are convenient, familiar, and easy to use. Books make a great deal of sense in the primary grades, and electronic textbooks much more sense in the upper grades and college.Slow, confusing, inevitable. And to show just how confusing it will be, we have two very different devices, the Kindle and the iPad, to choose from. Then take a look at what's coming: socially networked reading from http://www.copia.com/. Copia offers lots of different e-reading devices, but more importantly it offers a software platform and social network that differes significantly from Amazon and Apple. Craig Morgan Teicher writes a review of this service in MediaBistro http://www.mediabistro.com/ebooknewser/toc_2010/a_look_at_copia_152952.asp
He points out that the social networking service is set up perfectly to promote sharing of notes associated with reading: Blackboard or Moodle wedded to your textbooks.
Lots of different devices, lots of different ways to read, lots of books still being printed, sold and read on paper. The change will be slow, confusing and inevitable.
Oh and BTW: I predict the iPad will fall right between the Touch and iPhone in popularity. Remember that Apple is like Harley-Davidson, whose customers voluntarily tattoo the company's name on their bodies. 300,000 people were going to buy the iPad before it was even invented. People predict that some 3,000,000 kindles have been sold since it came out.