The Mozilla Foundation (http://www.mozilla.org), which created the popular new web browser, Firefox (http://www.mozilla.org/products/firefox/), has released version 1.0 of its new e-mail client program, Thunderbird (http://www.mozilla.org/products/thunderbird/). I've been using it since July 2004 (pre-release version 0.7), and highly recommend it. Thunderbird is available for Windows, Linux, and Mac OS X.
(http://www.mozilla.org/products/thunderbird/buttons/reclaimyourinbox_large.png) (http://www.mozilla.org/products/thunderbird/)