I discovered a neat feature: iChat will allow drag and dropping of vCard items into the Buddy List.
A friend sent his vCard export to me for inclusion into my Address Book. I noticed that he had an iChat entry in the Address Book and on a hunch, tried dropping the same vCard into iChat. Pretty slick.
Give it a try...
Mac OS X Hints
http://hints.macworld.com/article.php?story=20030109065457337