SpamMover for Exchange 2000 application can create a folder named Spam in each Exchange 2000/2003 mailbox and move any ingoing message that marked with specific mail header by anti-spam software like SpamAssasin, to that folder. You can set up SpamMover on per-mailbox basis or as store-wide application, i.e. it will work on each user's Inbox in the certain Exchange 2000/2003 mailbox store.