I had someone complain about the old winmail.dat problem the other day. I've seen it many times, and have always put it down to Outlook.. but while googling for a good explaination which would make sense to this guy, I came across a fix for it. The fix was mentioned by both
Chris Linfoot and on
Dominodude, and comes in the form of a handy little agent which makes use of the open-source and GPLed JTNEF library by Amichai Rothman.
Grab it here, from NSFTools - it works, and it works well!