Ruby on Rails is an open source full-stack web framework designed for programmer productivity and happiness. It has a high learning curve compared to PHP/MySQL, which it replaces in a web stack. Here are some Rails Notes
Click here to download the Rails lecture slides.
Rails Guides - good beginner tutorial, but also lots of thorough documentation
Ruby on Rails Tutorial - the sample app from the lecture came from this tutorial. Excellent comprehensive intro, reputably one of the best resources, but quite lengthy and with a focus on test driven development.
Rails for Zombies - short, fast intro to Rails with hands-on in-browser exercises.