If you missed this (I did :( ) we recently updated the Windows Mobile and Exchange 2003 Deployment Guide.
The updates include:
· Corrections/additions from customers and partners
· A new section on Network Architecture Alternatives with overview table and caveats for specific configurations
· More details about direct push technology
· Streamlined “Best Practices” section
· Instructions for deploying with ISA Server 2006 (original instructions for ISA Server 2004 were moved to an appendix)
· A Troubleshooting Appendix introducing tools and covering issues relating to direct push implementation, ISA Server, Front-end/Back-end communication, and certificate implementation on the server
· A shorter Quick Start Guide version (only 10 pages!) that presents the requirements, resources, network architecture alternatives, and an overview of the process in an easier to digest format.
We are also working one one for Exchange 2007 too... but in the interim - here is the DOC