Thunderbird will allow you to share a single profile between windows and Linux if your machine is a dual boot..
http://kb.mozillazine.org/Roaming_profile
Typically I just copy the profile folder then edit the profiles.ini to the new profile name. DONE.. profile imported. works on Windows or Linux
/home/username/.mozilla-thunderbird/profiles.ini
c:\Documents and Settings\username\Application Settings\Thunderbird\profiles.ini