The problem with that is that RoR is moving forward very quickly, and as such the books are having trouble keeping up. Having said that the Agile Web Development Version 3 (www.pragprog.com) is probably a good book to get you going with Rails 2 and then you could use the internet to keep up with the changes for 2.1 and the soon to be released 2.2
Another piece of advice would be to learn a bit of Ruby independant of Rails first so you don't have two Mountains to climb all at once, get comfortable with some Ruby, then take that to Rails. People say the learning curve for Rails is steep, but I don't really agree with that, they just take on too much all at once.
Good Luck, Rails is a lot of fun.