I liked the book (except the errors) and I have not done enough Rails to know how much the changes for Rails 2 not learned from the book will annoy me. I recently picked up the book "Simply Rails 2", but have not started it yet.
Rails 2 came out at the end of 2007 and we are now almost three years from then, and Rails 3 is now in beta. Software has bugs, books have bugs. You have to start someplace. Learning the most common structures of the earlier versions will allow you to read older code.