I received my first author copies of The Mac OS X 10.6 Snow Leopard Pocket Guide this week, and they look great! I also checked Amazon.com this morning and saw that the book is now in stock and available (and still costs only $10, with free shipping for Amazon Prime members!).
Peachpit has also posted an excerpt from Chapter 2, which covers installing Snow Leopard (here’s a direct link to the PDF) if you want to get a sense of the book’s content.