Windows & .NET Magazine author Paul Robichaux wrote a book, "Secure Messaging with Exchange Server 2003," which is published by Microsoft Press. An excerpt chapter from the book, "20 Tips on Securing Outlook in 20 Minutes," is now available online that helps people secure their Outlook clients.
In the chapter Robichaux helps reader understand Outlook's security features, how to customize the Outlook Security Update feature and security features for end users, how to establish RPC over HTTP, using S/MIME and Information Rights Management, how to use junk mail filters and address filters, encryption, and much more.
You can read the chapter online or download a version in PDF format.