Ruby on Rails is fast displacing PHP, ASP, and J2EE as the development framework of choice for discriminating programmers, thanks to its elegant design and emphasis on practical results. RailsSpace teaches you to build large-scale projects with Rails by developing a real-world a social networking website like MySpace, Facebook, or Friendster. Inside, the authors walk you step by step from the creation of the site's virtually static front page, through user registration and authentication, and into a highly dynamic site, complete with user profiles, image upload, email, blogs, full-text and geographical search, and a friendship request system. In the process, you learn how Rails helps you control code complexity with the model-view-controller (MVC) architecture, abstraction layers, automated testing, and code refactoring, allowing you to scale up to a large project even with a small number of developers. This essential introduction to Rails provides The book's companion website provides the application source code, a blog with follow-up articles, narrated screencasts, and a working version of the RailSpace social network.
One of the few books on building social networking sites. While not necessarily production-level code (nor is it the author's intent for this to be so), there is enough here to get you started. I actually read this book twice, building the entire site as I went - first with Rails 1.2 and later with Rails 2.0.2. My Rails knowledge was definitely improved after working through this book, including the all important aspect of testing.
One note - the book is written for Rails 1.2, but the authors have graciously kept things current with a blog and downloadable 2.0 source code (though I believe it was Rails 2.0.1 and a few things changed in 2.0.2, in particular the setup method in functional tests). The blog also includes updates on how to replace the deprecated and now removed built-in paginate (BTW - will_paginate is now a Gem, don't bother looking for the plugin).
All in all, a great learning experience - I'd recommend any books in the Addison-Wesley Professional Ruby Series (you do have "The Ruby Way," don't you?)
This book does a great job of stepping you through the construction of a real world project. It not only tells you how to do things but why certain approaches are taken. For Ruby on Rails newbies (like me), the authors also provide some great insight into how ruby developers approach projects and the culture in general. I've read about 2/3 of this book and haven't had to write a line of code myself in order to understand what's going on. Very valuable.
I am teaching myself Ruby on Rails and this book walks you through building a MySpace type website. No better way to learn than plodding through examples. Good book.