Mozilla Firefox is gaining in popularity with Web users because of it's tabbed browsing, pop-up blocking, and extendability. You can do many things with Firefox that you can't do with the "other" Web browser. Learn more.
Firefox Secrets - Book Review
If you need help learning about Firefox this book is a great place to start.
Get Firefox Extensions
Firefox extensions are what make Firefox so powerful. There are extensions for nearly everything you might want to do with your Web browser, and some that you didn't even know you wanted to do.
Firefox Google Toolbar
Get all the features you're used to with the Google toolbar in your favorite browser: Firefox. Things like spell checking and power searching, plus page rank and more.
PrivacyFox - mozdev.org
A Firefox extension that allows Firefox to read P3P policy files in a similar way to Privacy Bird (which is IE only).
Promote Your Site with a Firefox Sidebar
Firefox sidebars are an easy way to promote your site to Firefox users.
How To View the HTML Source in Firefox
Viewing the HTML source is one of the easiest ways to learn how someone did something on a web page. And imitation of HTML source is a great way to learn HTML. This how to shows how to view the source in Firefox.