well might as well throw my $0.02 in
the easiest way i did this:
1. install thunderbird in windows
2. use it to import all of my email
3. reboot to linux, install thunderbird there.
4. rename profile directory of linux install
5. copy the entire profile folder of the windows install to the profile folder in the linux install
6. rename the profile folder that you copied from windows to the linux folder name, should be a whole chunk of crazy chars.