Ubuntuland

Mozilla thunderbird stores your email and profile setting in a special directory called ~/.mozilla-thunderbird i.e. /home/you/.mozilla-thunderbird/

All you have to do is backup this directory.

Task: Backup Thunderbird mail and profile

You need to backup thunderbird mail and profile to tape drive, use:
# tar zcvf /dev/st0 /home/you/.mozilla-thunderbird/

You need to backup thunderbird mail and profile to a /backup directory:
# tar zcvf /backup/email-vivek-12feb2008.tar.gz /home/vivek/.mozilla-thunderbird/

You can copy /backup/email-vivek-12feb2008.tar.gz file to a CD/DVD or USB pen.

Task: Restore Thunderbird mail and profile

Make sure Thunderbird is not running. Simply copy backup files fromh tape, USB pen or CD to your /home/you/.mozilla-thunderbird/ directory:
$ tar –zxvf /backup/email-vivek-12feb2008.tar.gz -C /home/vivek

Or just copy all files from USB pen/CD to ~/.mozilla-thunderbird/ directory.