That's why it's important to sell more than just an ebook. I included 2 full languages you can use in OSS, http://jashkenas.github.com/coffee-script/ started from the Ruby language included in the package. + screencast and more.
Also the book is amazingly good :p
Taking advantage of "This is a not a dead tree" is sorely lacking in the E-books I see. Even the page layouts of E-books assume you're using some shaped-like-a-page viewer, rather than allowing for a flexible layout that works well across different screens and devices.