Railscasts.com is a free video tutorial site for people who wants to learn Ruby and/or Ruby on Rails and related libraries.
Taken from the website:
Every week Ryan Bates will host a new Railscasts episode featuring tips and tricks with Ruby on Rails. These screencasts are short and focus on one technique so you can quickly move on to applying it to your own project. The topics target the intermediate Rails developer, but beginners and experts will get something out of it as well.