Right now there's just a PDF, but I'm working on getting it into the kindle store. If you'd like a PDF before the Kindle copy comes out, send me an email (rdegges@gmail.com) and I'll send you a free one to hold you over :)
I was actually about to ask the same question. I haven't seen the book but I expect it contains a lot of command line snippets and code, and in my experience the Kindle does a ... shall we say unsatisfactory job of rendering those.