If you've heard of Rails, and you're not sure where to start, this post is for you.
First, you need some motivation. What can Rails do for you? Watch the Screencasts of Ruby on Rails. This will give you a taste of how productive (and fun) the Rails environment is. To understand some of the philosophy behind Rails, view the RailsConf 2006 Podcasts; in particular, the keynotes by Fowler and DHH. You should now be ready to dive into Agile Web Development with Rails. This will teach you everything you need to start writing Rails code.
Okay, now that you have the basics, what next? Read The Rails Way, a site illustrating the "proper" way to write Rails code. For more Rails education, view the PeepCode Screencasts.