From OCS Support Wiki

Introduction

This guide will show you how to create a rule in Outlook that will move SPAM that SpamAssassin identifies into the Junk E-mail folder in Outlook. These instructions only work for Outlook, and not Outlook Express. These instructions were created specifically for Outlook 2007, so if you have an earlier version they may differ slightly.

Creating the Rule

• Go to the Tools menu, click Rules and Alerts
• Click New Rule
• Click Check messages when they arrive and click Next
• Check With specific words in the message header
• Click the words specific words in the box below the selection and put X-Spam-Status: Yes, click Add, then click Next
• Check Move it to a specified folder
• Click the word 'specified' on the third line in the box below and select your Junk E-mail folder (or whatever folder you want to move SPAM into) and click Next twice
• Name the rule SpamAssassin, or another name if you wish, check Run this rule now on messages already in Inbox if you want it to do so, and click Finish

SPAM that SpamAssassin identifies will now be moved automatically into the Junk E-mail folder.