I couldn't figure out how to export my Outlook 2000 contacts to the Windows Address book, but I found a pretty quick and easy way to sync my contacts anyway.
First, I exported my Outlook contacts to a .csv (comma separated values) file. I then set up a gmail account and imported my contacts into that. Finally, I set iTunes to sync contacts with Google Contacts.
Works beautifully, if somewhat inelegantly. Not wanting to leave all those contacts online, I deleted them and turned off contact syncing. The whole process took maybe 10 minutes (including creating the gmail account) so it's not much of a hassle to update contacts when needed.