Learn Plover, Zachary Brown's online steno textbook, will always be available on the website for free. But several people requested a print version, so it's now available for purchase!
Buy Learn Plover in paperback from Amazon here. It will also be available as a Kindle ebook in the near future.
He's also been working on a new Velotype-style orthographic chording system, called Kinglet, which he thinks might have an easier learning curve than Plover. It's not yet compatible with any software, so he doesn't have videos of it in action, but it should be pretty simple to implement. If this sounds like your kind of text entry system, go check it out!