AD RMS can be used to protect Microsoft Office SharePoint Server 2007 document libraries.  If you would like to integrate your SharePoint server with AD RMS here are a few links to get you started:

• The AD RMS Deployment with Microsoft Office SharePoint Server 2007 Step-by-Step Guide guides you through the process of deploying AD RMS and Office SharePoint Server in a test environment.
• The topic Secure Collaboration Using Federated AD RMS with Microsoft Office SharePoint Server 2007 contains several articles about using AD RMS with Office SharePoint Server, including how to integrate AD RMS and Office SharePoint Server 2007 and how to provide external partners with secure access to protected libraries by using AD FS.
• The Secure Collaboration using AD RMS, MOSS and AD FS podcast will teach you how to integrate AD RMS and Office SharePoint Server and also how to use AD FS to provide single sign-on (SSO) access to protected document libraries.
• Learn how to enable AD RMS and Office SharePoint Server integration in the AD RMS Integration with MOSS, Exchange and Windows Mobile TechNet Virtual Lab. In this lab you will integrate AD RMS with Office SharePoint Server, create a protected library, and verify AD RMS functionality in a virtual lab environment.