I finally got Firefox and Thunderbird talking to each other!  Now when I 
click on a link in a mail message, Firefox launches a new tab, and when 
I click on a mailto: link in Firefox, Thunderbird launches a new mail 
message.  I'm using Firefox 0.9, and Tbird 0.7, and they are both very 
fast with some great features.  It's too bad that making them work 
together is a PITA.  It's my understanding that someone is working a UI 
for what I had to do with config files and extensions.

Just thought I'd share a victory with you all.  :-)

Peace,
Jim