Ingo Ramer posted a number of his white papers targeted at application architects, designers and developers who are working with .NET and Web Services technologies. Currently there are 3 available but 4 more are coming soon. My personal favorite:
The Flowchart Lieor: Why do we still use request/response to handle asynchronous business processes?
These come highly recommended since Imgo is one of the most knowledgeable in the field (and not yet swallowed by the big house).