By creating a custom outlook form.
The 'how' of doing that is left as an exercise for the reader. It's
non-trivial but not hard.
In my old OL2000 steup I modded my Contact form to have fields for Y!M,
ICQ, MSN instant messaging services. :)

Bear
p.s. you might want to NOT show your real email address in a newsgroup
posting.  It's a SURE way to get more spam.