I've been asked a good number of times about how to go about learning Ruby and Rails... for learning Rails, my answer is simple: learn Ruby first and then pick up Agile Web Development with Rails. (There are already a good number of "Rails programmers" who don't know much of Ruby... let's not add more please.)
Learning Ruby is trickier. I typically do not rely too much upon books as a starting point (as it may quickly get boring and may make you lose pace). I rely more on reading and understanding other people's code (as that's more interesting and also leads you to learn language-specific idioms... but you should be selective about whose code you wanna emulate). I do cover specific basics of any new language though as first steps.
Personally, I learnt Ruby mostly from these sources:
I've listed some more helpful links that you should check out.
If you're just looking for reasons why you should start looking into Ruby, try this article that I'd written for a magazine: Ruby: a gem of a language