Exchange 2000/2003 RUS not updating certain objects?

This is a great article for troubleshooting issues in which the Exchange 2000 or 2003 Recipient Update Service is not stamping particular object or objects in particular OUs:

http://support.microsoft.com/kb/254030

Outlook 2007 Autodiscover Whitepaper

Microsoft Office Outlook 2007 includes the ability to automatically configure user accounts. Outlook uses one of two discovery mechanisms to automatically configure accounts: Autodiscover and Common Settings Discover. This whitepaper describes how the discovery mechanisms work, and how an administrator can modify settings in an XML file to configure Autodiscover for an organization.

Outlook 2007 Autodiscover Whitepaper