Interested Firefox and Thunderbird user.
Current pet project: Writing an nsIImportModule in order to import mails, settings and the address book from The Bat! 1.x to Thunderbird.
Current status: (August 2007) I produced a small basic "extension" containing a few hundred lines of code. There is now a new item in the Thunderbird 'Import' dialog when importing mails called "The Bat! 1.x". The mail import factory is returned and could begin its work. Next steps include adding some 'fake progress' and writing a C library (preliminary named 'libbatmail') which can be included in the extension at a later point to do some real work.
See TheBat Importer (en) for more information about the reverse engineered file format and related tools. bug 217988 ("import mail and settings from The Bat! mailer application") is the official bug report for this feature.