Here's a good Article, on how to import and export mail into the Free and Open Source, Thunderbird e-mail App. Also, check out the links below for more info on Thunderbird...

Don

Importing and exporting your mail

(Redirected from Thunderbird : FAQs : Migration)

This article was written for Thunderbird but also applies to Mozilla Suite / SeaMonkey (though some menu sequences may differ).

[hide]

[edit]

Introduction

If your old email client is still installed, the easiest solution is to import the e-mail, address books and settings using Tools -> Import. If it is not installed or Thunderbird doesn't know how to import data from it, typically you need to find some way to export or convert your old email client's mail files to either .EML or mbox files, and some way to export or convert the address books to .CSV or .LDIF files. And if you just need to transfer email between email clients, another option is doing so indirectly via a mail server.

Thunderbird, Netscape, Mozilla Suite and SeaMonkey use mbox files to store the messages for a folder. The ImportExportTools extension can import and export mbox and .EML files. Many email clients use mbox files (regardless of whether they use no file extension, .mbx or .mbox as the file extension) to store messages or provide a way to export folders as mbox or .EML files due to the popularity of Eudora and Outlook Express. Sometimes email clients use "Unix format" to refer to a mbox file since the format was originally developed for Unix systems.

If you have problems importing .EML files using the ImportExportTools extension try using eml2mbx to convert the .EML files to a mbox file and then import the mbox file using the ImportExportTools extension. A Google search will find several eml to mbox conversion programs. Whats unusual about this one is that provides a lot of control over how it converts the .EML files using a "eml2mbx.ini" file.

If your old email client supports exporting the address book as either a .CSV or .LDIF file you can import it using Tools -> Import -> Address books -> Text Files. If not you might be able to use a program like Dawn to convert the address book to a .CSV file and then import it.

No matter how you import or export your e-mail its a good idea to back up your e-mail first in case something unexpected happens.

If you're moving from a old PC to a new one its typically easiest (and safest) to install Thunderbird on the old PC, import your e-mail, settings and address books and then move the Thunderbird profile to the new PC.

Specific programs

Read More...
http://kb.mozillazine.org/Thunderbird_:_FAQs_:_Migration

ImportExportTools

ImportExportTools allows the user to export and import messages with more flexibility, with the following options:

Tools Menu --> ImportExportTools
Context menu on folders panel --> Import/Export

- export of folder in a single file (mbox format), with also the subfolders if you want;
- export of all messages in single files (eml format);
- export of all messages in single files (html or plain text format), with an index;
- export of all messages in one single plain text file;
- export of index of the messages in a folder (HTML or CSV format); - mbox files import;
- eml files import;
- import of all the eml files existing in a directory;
- export of all files of all mail files of the profile (just from the "Tools" menu);
- search with various criteria and export messages;

File menu --> Save selected messages
Context menu of thread panel --> Save selected messages

- saving multiple messages in eml/html/plain text format with just a click;

Message menu --> Copy to clipboard
Context menu of thread panel --> Copy to clipboard

- copy the message or all headers to clipboard.

Context menu on an EML attachment

- import file in the folder

To install the extension, follow this procedure:
- download the xpi file that you find in this page or in the homepage, right clicking on the link and choosing "Save target as";
- in Thunderbird, go in "Tools" --> "Addons" (or "Extensions") and click on "Install";
- pick the xpi file you downloaded and follow the instructions;
- restart Thunderbird.