O’Reilly now has their own version of the Beta Book. They call it Rough Cuts. Right now they have three titles I am looking at, Ajax Hacks Ruby Cookbook and Ruby on Rails: Up and running
Agile Web Development with Rails looks like a more advanced Rails book than the Ruby on Rails: Up and running but the Ruby Cookbook looks good. Especially since I am trying to build my own recipes from what I found on the web.
All in all, it is good to see more people embracing the idea of early releases to help ‘test’ books. I found it enjoyable to read the drafts of the book and follow in the progression to a final product.