On the 2nd June 2004, Microsoft release an add-in to the Exchange 2003 called Exchange Intelligent Message Filter. (Build 06.05.7202)
Intelligent Message Filter is based on Microsoft SmartScreen Technology from Microsoft Research. By using e-mail characteristics tracked by SmartScreen technology, Intelligent Message Filter can help determine whether each incoming e-mail message is likely to be spam. Based on this likelihood, you can choose to block e-mail messages at the gateway or at the mailbox store. For more information about Intelligent Message Filter, see Exchange Intelligent Message Filter Overview.
You can download it by going to the following link: http://www.microsoft.com/downloads/details.aspx?FamilyId=C1B08F7B-8CAF-4147-B074-8C9C8F277071&displaylang=en
MOM management pack
In addition they have also released a MOM management pack (Build 06.05.7226). You can download it from:http://www.microsoft.com/downloads/details.aspx?FamilyId=2537C08E-26F3-4146-9C7C-2DF622BDC29D&displaylang=en