Contacts:
In Tbird, open the address book.
Tools - Export
save as LDIF or CSV
In WM, file - Import - Windows Contacts
Messages:
Get the ImportExport message extension for Thunderbird and install it...
http://nic-nac-project.de/~kaosmos/mboximport-en.html
Tbird:
highlight a folder
Tools - Import/Export in mbox/eml format - Export all messages in the
folder - EML format
pick a location to save the files
OK
the files will be saved in a subfolder
(do this for all the folders)
Windows Mail/Windows Live Mail:
File - Import - Messages - Windows Mail 7/Windows Live Mail
select the folder location you saved the files to
next
All folders
next
Finish
But why bother? Tbird is better than WM, which was rushed out the door, and
has already been deprecated in favor of Windows Live Mail.