Thunderbird is probably the most configurable and customizable email program available today. No other email program allows the extensions, user interface look and feel, and features that Thunderbird offers.
Thunderbird is easy to install, involving just a simple download (like Firefox) from http://www.mozilla.org. Versions of Thunderbird are available for Windows, Linux, and Mac OS X.
Thunderbird does an excellent job of moving your email, folders, and settings from Outlook, Outlook Express, and Eudora to Thunderbird.
Account setup is straightforward and easy. Wizards are provided to help make the setup steps easy and understandable.
The Thunderbird email editor is easy to use and offers spell-checking and formatting.
If you like HTML email, Thunderbird is capable of creating your formatted email without relying on complex and difficult-to-use HTML editors.
Thunderbird is ready to work with RSS feeds and blogs, requiring only a simple setup to get going.
With Thunderbird, you can access NNTP newsgroups much like Outlook Express does.