I came from a PHP / CodeIgniter background, I spent a couple of hours with Rails for zombies, and then just started playing around with rails, using http://guides.rubyonrails.org and http://railscasts.com when ever I could't figure something out. And of course, stackoverflow is a great resource.
Don't forget about the official Rails guides themselves, they are actually quite helpful.
I go back and forth on whether learning Ruby first is best. You will learn more about Ruby itself just by solving RoR problems, but I think you would solve them faster if you already had a solid base in Ruby.
If you go RoR way - Michael Hartl's tutorial - http://railstutorial.org/ is probably the best place to start (I did that when I was starting with RoR). Codelearn - www.codelearn.org should be the next best.
Disclaimer: I am the founder of Codelearn
Codeschool has some great courses in general. Their courses require a monthly subscription, however, if that matters to you.
