Creative Commons Add-in for Microsoft Office 2007
Here's a nice Office 2007 add-in that let you insert in your Word, Excel and PowerPoint document a Creative Commons license like the ones found here: http://creativecommons.org/about/license/
While not a DRM, it simply states how you'd like other people use your work like slides from a presentation you made at a user group meeting.
The add-in creates a new tab where you can create a set of licenses and add them easily to your documents.
Download the add-in here:
http://www.microsoft.com/downloads/details.aspx?FamilyID=D1DDBDC8-627F-415A-9B0A-97362BC9B480&displaylang=en