Getting Started with Drupal
Note: I wrote this a few years ago so you'll notice that references here are for Drupal 6. Some of the books have been revised and re-released for Drupal 7. I hope you'll look into them as you pursue learning Drupal.
Quite a few people have been talking to me lately about wanting to get started making websites with Drupal, so I thought I would share here some of most useful tools and resources that I've found:
1. The Drupal Community as found at drupal.org. This open source community is your source for everything from core source code and contributed modules and themes, to discussions, case studies and technical support.
2. Building powerful and robust websites with Drupal 6 by David Mercer. This book gives a great big-picture overview of Drupal, a lot of practical information, and hands-on exercises. This should be your first Drupal book.
3. Using Drupal by Jeff Robbins, Angela Byron, Addison Berry, Jeff Eaton, Nate Haug, James Walker. This book takes your Drupal to the next level, taking you step by step through case studies that illustrate how to integrate the most powerful Drupal modules. It will help you make sense of the dizzying number of modules found on drupal.org.
4. W3Schools Online Web Tutorials. Drupal is a powerful tool that leverages your knowledge of web programming, but it doesn't eliminate the need for it. You still need to be able to find your way around html, css, php, and to some degree SQL & jQuery. This website is a great resource if you need to look something up or remediate your skills.
5. Drupal 6 Themes by Ric Shreves. This book will give you the knowledge and best practices for making your site look the way you want it to look.
6. A daily walk. You need a healthy mind and body if you want to be productive and creative behind the computer. Get outside, breath some fresh air, see some beauty and get your pulse rate up. Your brain needs oxygen.
7. Firebug. This add-on to Firefox is a great tool for figuring out what code in which file is causing a behavior. It's also good for looking at other websites and seeing how things are done.
8. Pro Drupal Development second edition, by John VanDyk. This book delves into the nitty gritty of the technical details of the Drupal core and modules. It's not always necessary to get into this level, but it's very reassuring to have this book as a guide when you do.
These are the resources I've found most useful so far. I hope you find them helpful too. Let me know if I've missed your favorite!