We've published in Internet@Schools and here at Internetatschools.com online quite a number of articles and columns on the ebook (see Stephen Abram's recent Pipeline column, for instance, as well as Victor Rivero's Tools for Learning ebook update piece). Here's a brief piece from Edutopia that adds a lot to the discussion, in our opinion, largely owing to its focus on resources for "doing it yourself." First paragraph:
Textbooks are a multi-billion dollar industry -- an estimated $3.5 billion for the K-12 market alone. But the growing availability of digital content and open educational resources (OER) is giving schools the opportunity to bypass some of the traditional expenses of textbook purchasing. It's also giving teachers the opportunities to build their own textbooks.
Take a look for yourself; it's a quick, useful read. Building Your Own Textbook, at Edutopia.