The main thing you want to do when learning Rails is to make sure you're pretty solid in Ruby. David Black's Well-Grounded Rubyist covers a lot of Ruby.

As for Rails, I have nothing but good things to about Foundation Rails 2 by Eldon Alameda. He gives a brief introduction to Ruby at the beginning, and doesn't rely on scaffolding/plugins, something a lot of early Rails developers try and overuse. Although, now that I think about it, the routing chapter was a little weak. Of course there's also the standard Agile Web Development with Rails (3rd Edition) which was written by the creator of Rails.

After that, the best place is to start writing apps and get some hands-on experience. If you want, there's another book that Eldon Alameda wrote called "Practical Rails Projects" which does exactly that -- guides you through 6 or 7 Rails projects to teach you all about Rails. However, it uses an older version of Rails (1.2.3 compared to the current 2.3.3) but I'm sure a lot of the concepts will still apply. You can always install an older version of Rails to follow along.