SpamAware
Snapfiles have a free outlook add-in to help with the spam menance.
SpamAware is an Outlook add-in that uses the SpamAssassin engine to score email as it arrives in your inbox, and marks potential spam with a tag in the subject line, or automatically moves it to a JunkMail folder. SpamAware also supports Blacklist/Whitelist entries and can automatically add people that you communicate with to the Whitelist. Works well, but scanning of emails is very slow.
Download from here