Linux Textbooks?

whymw asks: "I am a computer science instructor at our local community college where I teach an introductory level Linux course. Due to worries about Microsoft licensing, my director is interested in moving other courses such as office packages to the Linux environment. However this question keeps poping up - 'What would we use for textbooks?' There is little to pick from and I see this as a major barrier to widespread adoption of Linux in the classroom. Do we need to create a linuxtexts.org? Should openoffice.org fork off a textbook project? By the way, I said TEXTbook, complete with labs, assignments, and hopefully a testbank." Linux has to make it into the education market at some point. If there are no Linux textbooks out right now, what recommendations would you have from the current crop of off-the-shelf books?