Reliable way to detect presence of macros

What I'm looking for is a reliable way to detect the presence of macros in

Word 6/7/97/2000/2003 documents.

Would help if this could be done for Excel workbooks too, but not essential.

I don't need to know what macro names, or what code they contain, just if

macros are present, true or false. That way I can code a (hopefully small)

executable to detect them. This is to implement a mailserver policy for a

distribution-list that needs to send Word documents, to ensure no macro-based

malware gets through.

Does anyone know of any relevant Technet articles or code examples?