As of now, the second edition of Test Driven .NET Development with FitNesse is free online. You can download the full PDF version or read the book online in HTML at http://gojko.net/fitnesse.
What’s new in this version?
Since the book was originally released, both FitNesse and the .NET FIT test runner were improved significantly. All the examples in this book are now updated to be compatible with the latest releases of FitNesse (20091121) and FitSharp (1.4). I re-wrote parts that are no longer applicable to the new FitSharp test runner, especially around Cell Operators. In a classic example of self-inflicted scope creep, I also wrote a new chapter on using domain objects directly.
I also changed the tool used for assembling the book. Instead of Apache FOP, I used XEP which will hopefully make the layout a bit better. Fonts (especially the code font) were also changed to make the book easier to read.
What about the paperback
I will make the paperback available soon. At the moment, the second edition is only available online.