With over 2,000 modules to choose from, and more added every single day, finding the contributed module you need for a given task can be a daunting process. The first step to choosing the right module for your needs is actually finding it. Fortunately, all Drupal modules (with only a few rare exceptions) are located directly on the main Drupal.org website, so there's only one resource necessary for finding them. Here's how you do it.
[Remember: Drupal 5.x modules are not compatible with Drupal 6.x, and vice versa. To see an accurate list for your site, make sure to change the "Filter by Drupal Core compatibility" filter to show only those modules that are compatible with your Drupal version. You will have access to apply this filter only if you are logged in to the Drupal.org website. Getting an account is free and easy, and opens up many useful tools to you.]
Browse Module Listings
The module listing pages list modules by category (such as CCK or mail-related modules), by name alphabetically, and by the date they were last updated. Another nice Drupal.org "hack" is keeping an RSS reader pointed at a list of all the newest modules on Drupal.org as they are created.
Drupal.org also provides a block for searching the downloads on the site. For example, searching for "wiki" brings up a list of modules with that keyword in their name or description. This allows you to drill down to modules specific to your needs faster than browsing by the default category view.
The Drupal.org support forums, particularly the "Before you start" forum, can provide a wealth of information in the form of questions from other users about the modules they used for their own projects. The "Drupal showcase" forum is also filled with people showing off websites they built with Drupal—and they are often more than happy to share details about how they built a particular piece.
Chances are good that no matter how crazy the use case, someone else has had to solve the very same problem with Drupal as you have. You can cut down the time required to find modules tremendously by finding out how they went about it. The Drupal handbook contains a section for case studies.
Planet Drupal is an aggregation of Drupal contributing members' blogs and is a great way to find out what's new and hot in the module world. Module tutorials, reviews, and news are often posted there, and Planet Drupal also a great general resource for keeping your finger on the pulse of what's happening in the larger community.
Drupal.org provides a list of third-party websites—that is, separate from Drupal.org—that often provide useful information when evaluating modules. For example, drupalmodules.com provides user ratings and reviews of Drupal modules, and lullabot.com has a variety of articles, videos, and podcasts, many of which highlight popular modules and how to use them.
Learn more about this topic from Using Drupal.
With the recipes in this book, you can take full advantage of the vast collection of community-contributed modules that make the Drupal web framework useful and unique. You'll get the information you need about how to combine modules in interesting ways (with a minimum of code-wrangling) to develop a variety of community-driven websites -- including a wiki, publishing workflow site, photo gallery, product review site, online store, user group site, and more.