Check out Nokia Web Services Framework for Devices — a Service-oriented Architecture. It’s a practical intro to how SOA might play in the mobile space, with some eminently sensible background work; there’s a section entitled What is a service-oriented architecture, and why is it good?. Anyone who doesn’t think that the center of gravity of networked computing, which means all computing, is moving toward the mobile space and isn’t reading Russell Beattie and probably should be. As I’ve said before, if you want to know the future of SOAs and Web Services, look at the people who are actually deploying them and see what they’re doing. Anything they’re not going to use, you can ignore for now.