rubyonrails.de published an open sourced Ruby on Rails 2.0 book. It's currently only in german, but we hope that it will also be translated into english. If someone is able and have time to do this: send me an email The first edition covers the installation, configuration and a HelloWorld example. The second chapter will follow soon. We currently updating it to Rails 2.0.
Details (Sorry, but also only in german): http://www.rubyonrails.de/newsitems/98
Have fun with it and we hope you like it (at least the idea
Cheers + Merry Christmas derKaan