While you can select a single Outlook contact, choose File -> Save As and, in the resulting dialog box, choose vCard Files from the Save as Type pop-up menu, this works only for individual contacts—you can’t export a group of contacts this way.
You have a few options for eventually getting the things out of Outlook. The first is to select all your contacts and choose Action -> Forward as vCard. Outlook will create a new email message that contains all your contacts as individual vCard attachments. Send this message to yourself, pick it up on the Mac, drag these files into Address Book or Entourage’s Address Book and you’re good to go.
EDIT: I can't take credit. I just did this.
http://www.google.com/search?q=expor...ient=firefox-a