QUALCOMM and Mozilla Develop Open Source Version of Eudora Email Program - QUALCOMM Incorporated and the Mozilla Foundation, today announced that future versions of Eudora® will be based upon the same technology platform as the open source Mozilla Thunderbird™ email program. Future versions of Eudora will be free and open source, while retaining Eudora's uniquely rich feature set and productivity enhancements. [GNUs]

It's now here - the project started by LUG Radio's very own Jono Bacon.
Well if you want to read more/see more look at jokosher.org and you can download it from jokosher.org/downloads.

Secure your email communication with free software - A guide for installing, configuring and using Mozilla Thunderbird, Enigmail, and GnuPG to provide secure and encrypted email [GNUs]

Highly recommended. I use enigmail too.