Tobii-Dynavox offers a selection of books that can be viewed on pretty much any computer. If you make a free account at mytobiidynavox, you can download these books, and lesson plans that come with them.
Like I noted, you can view these books on any computer. Or you could print and bind them. Or... and this is the solution that I really like... if you have an iPad, you can save the books in iBooks, and access them anywhere, even without wifi.
Take a look at the video to see the process.
Incidentally, if you really like these books, and prefer old-fashioned paper-back, you can purchase 36 of the books here, for $169.50.
ADDENDUM: Hey Tek-ninjas, I’ve had a professional license with Tobii-Dynavox for so long that I forgot that if you don’t have a professional license your myTobiiDynavox webpage looks different. Some of you may not have set up a professional license yet and so you’re not able to find these great resources. Take a look at this quick video as it will show you how to set up that professional license. Again, this remains free. Incidentally, the Professional account also affords you a free copy of Snap + Core First.