LookOut is a plugin which allows Thunderbird (and SeaMonkey) to interface with Microsoft's mail tools by decoding metadata and attachments encapsulated/embedded in a TNEF encoded attachment (aka winmail.dat).
The TNEF decoding engine was inspired (with permission) by the TNEF project. LookOut has a full MAPI decoder and the ability to transcode some of those properties to iCalendar (ics) and vCard (vcf) formats.
As an option all MAPI properties within a email can be viewed so other types of information can be deciphered.