What is the best way to learn ruby
There are some good books at the Pragmatic Programmer:
For complete beginners:http://pragprog.com/titles/ltp2/learn-to-program-2nd-edition
And more advanced:http://pragprog.com/titles/ruby3/programming-ruby-1-9
I completely agree with ralph.m on the beginner book, but I'd replace the more advanced with The Well Grounded Rubyist by David A. Black.
I found the Pickaxe (Programming Ruby) to be a good reference, but I couldn't learn Ruby from it.