I have been trying out Thunderbird as my sole e-mail client for about two months now. My impression is a favorable one thus far, but one feature I found I missed from Outlook was its integrated calendar function. So I recently tried out the Mozilla Lightning calendar add-on and find that for my needs it seems to work fine. This is new software, version 0.3.1 as of Feb. 19, 2007 and is probably not ready for prime time, but I’ve had no problems after several days of use. You can down load it here:
http://www.mozilla.org/projects/calendar/r…tning0.3.1.html%5B/url%5D
Paul