At TechEd 2005, Microsoft announced the Messaging
and Security Feature Pack for Windows Mobile 5.0. The combination of Windows Mobile 5.0 with Exchange 2003 SP2 will offer Windows Mobile Direct Push Technology to provide always on capabilities for email and appointment schedules, improved security management, wireless support for contact information (like doing lookups of global address lists stored on an Exchange Server) and improved management of device security policies (such as certificate-based authentication).
The Messaging and Security Feature Pack for Windows Mobile 5.0 is expected in October 2005.