Thunderbird is an e-mail program created by the folks at Mozilla who claim it makes sending e-mail safer, faster, and easier than ever before.
Some of the benefits of Thunderbird include:
It removes spam and helps keep your Inbox clean.
There is a new three-column view to access your e-mail so you can view your e-mail the way you want it.
There is built-in spell checking.
It is safe and secure and provides enterprise and government grade security features such as S/MIME, digital signing, message encryption, support for certificates and security devices.
Unlike many other e-mail products, it doesn't allow scripts to run by default. This results in a more secure product than other mail clients on the market and helps stop the spreading of worms and viruses on the Web.
It has unlimited functionality through extensions. Thunderbird is packed with great features like IMAP/POP support, support for HTML mail, labels, quick search, a smart address book, return receipts, advanced message filtering, LDAP address completion, import tools, powerful search, and the ability to manage multiple e-mail and newsgroup accounts.
You may add additional features as you need them through extensions. Extensions are powerful tools to help you build a mail client that meets your specific needs. Take a look at the various extensions available.
You can personalize it with themes - just about any part of the interface can be changed with themes.
It is cross-platform! Windows, Linux or Macintosh? Regardless of your choice of operating system, Thunderbird is available. It currently runs on Windows 95, 98, Me, 2000 and XP, as well as Linux, MacOS X, OS/2 and Solaris.
It is absolutely free.