As you begin (and continue) your journey of learning Drupal, there will likely be times when you'll need to find a Drupal module, a Drupal theme, additional details about specific Drupal technologies (such as theming), and operating system level commands (like backing up the site from the command line). The following is a list of recommended web sites where you can find additional resources to help you along your journey.
The primary site for finding modules is the Drupal.org web site (http://drupal.org/project/modules). Every Drupal contributed module has its own "homepage" that describes the module, provides links for downloading the various versions of the module, and, in most cases, links to additional documentation and examples.
Another site that provides a slightly more user-friendly interface is the Drupal Modules site (www.drupalmodules.com). This site provides a friendly search interface, user reviews, user ratings, most downloaded, most favored, and other value added services.
The primary source of Drupal themes is the Drupal.org web site (http://drupal.org/project/themes). You can browse through dozens of themes, see screenshots of each, and download the themes you like from Drupal.org.
Another useful site is the Theme Garden site (http://themegarden.org/drupal6/). Note: I assume that Theme Garden will develop a Drupal 7 site. This site is unique in that it is a Drupal site that allows you to change the theme of the site on the fly to see how a site looks using the various themes that are available on Drupal.org.
The Drupal community has assembled a number of online handbooks (http://drupal.org/handbooks) that are chock-full of information about Drupal. You will find handbooks that cover topics such as:
Getting Started
Understanding Drupal
Installation Guide
Administration Guide
Creating a Site
Structure Guide
Site Building Guide
Theming Guide
Writing Your Own Code
Developing for Drupal
API Reference
Reference
Tutorials
Drupal Cookbook
Tutorials
Videos and Slides
Community
About Drupal
Getting Involved
Documentation Team
One of the best sources for Drupal help is the forums on the Drupal.org web site (http://drupal.org/forum). There are hundreds of thousands of postings on just about every conceivable topic. If you run into an issue, you're likely to find that the solution to your problem is already documented in the forums. If you can't find a solution, you can post a question to the forums and receive a solution to your problem often within hours of posting the issue.
In Chapter 13 I talked about using the backup and migrate module as a means of backing up the database. You will also want to backup the directories on your server. There is a detailed description of how to do this on the Drupal.org web site (http://drupal.org/node/22281).
If you are looking for a place to host your web site, an excellent resource is the Drupal.org site (http://drupal.org/hosting). The hosting page lists a number of companies that are known to support Drupal.
A great resource to help you learn HTML and CSS is the W3Schools web site (www.w3schools.com/). You'll find easy-to-understand tutorials and excellent examples.
There are thousands of YouTube (www.youtube.com) videos that cover a wide variety of Drupal topics. It is a great source for learning various aspects of Drupal. Enter Drupal in YouTube's search box and you'll see a very long list of Drupal related videos.