[craigmc]

http://ruby.railstutorial.org/

Definitely worth buying his video series that accompanies the book (which is free online).

then:

http://railscasts.com/ (start with the early ones and work forward - I found these great to do at the end of a day)

Although I'd certainly also recommend the books that glasner mentioned, particularly "The Rails Way" by Obie Fernandez (although, from experience, it will freak you out a bit as a beginner if you try to read it cover to cover...)

Finally, http://stackoverflow.com/questions/tagged/ruby-on-rails - there won't be many questions you'll have initially that haven't already been the subject of a great answer (or indeed multiple great answers).