Good online Ruby tutorial? (for learning basic Ruby syntax)

I'm a CakePHP developer looking to give Ruby on Rails a try. I've never programmed in Ruby in before, so I need to learn enough of the language to jump into Rails. Are there any good online books/tutorials/ guides that you recommend?

Also, what differences can I expect in Ruby on Rails compared to CakePHP?

Thanks for the recommendation.. The tutorial is good

Check out the podcast for quick ruby tips!