If you are considering publishing Microsoft Exchange 2010 web clients (Outlook Web App or ActiveSync) I would strongly encourage you to read this highly detailed blog post on the subject posted recently by the Exchange Team. Of course Forefront Threat Management Gateway (TMG) 2010 includes native support for Exchange 2010 web clients, but if you plan to upgrade your Exchange infrastructure prior to migrating to TMG then this document should be considered necessary reading.
