As Byte56 points out, there are a lot of articles on the web discussing this topic. It's been a highly debated and discussed game developer topic for years now and probably will be for more years to come.
The reason why its still such a hot ticketed concept is because there really isn't a tried and true roadmap that describes how to manage, store, and relate entities and components. Just when you think you have a strategy on how you'll go about it, the next article you read may approach it from an entirely different angle, leaving you proposing some mixin or alternative all together.
My advice is to start small and simple. Don't try to design an Entity Component System with all the bells and whistles, just concentrate on a just a few specific features you want to try and explore. Tweak the design and don't be afraid to rewrite it if needed. Such a system can quickly evolve and as you add more behaviors and features, you'll find the need for more and more bells here and there which often require tweaks or even major changes.