Just a quick post to bring together some MSDN webcasts that you may want to have a look at if you're interested in using MSMQ or WCF (and maybe both).
MSDN Webcast: Using Asynchronous Patterns with Web Services
MSDN Webcast: Optimizing Scalability, Performance, and Availability with the .NET Framework (Microsoft Tech·Ed 2005)
MSDN Webcast: Using MSMQ to Build Reliable Mobile Applications
MSDN Webcast: Building Network-Aware Applications for Sometimes Connected Mobile Devices
Windows Communication Foundation.
MSDN Webcast: Windows Communication Foundation Top to Bottom (Part 14 of 15): Message Queuing
Migrating .NET Applications to Services Oriented Solutions with WCF