"Microsoft® Windows Mobile® 6 and its predecessor, Windows Mobile 5.0 with the Messaging and Security Feature Pack (MSFP), include many features that help you secure corporate infrastructure with minimal difficulty—and with minimal inconvenience for your users. Using Microsoft Exchange Server as the messaging platform further increases the security options available. In this article, I demonstrate how you can use Windows Mobile, Exchange Server, and some network security best practices as a foundation for protecting your company’s mobile devices."
This whitepaper in TechNet Magazine, July 2007, is a good technical overview to the security features embedded in WM6. Some of them are new and improved over WM5 -- such as remote storage card wipe -- so if you're an administrator looking to deploy mobile solutions in the corporate workplace, you'll want to have a look.