SML: As far as I can tell the real requirements for us break down into four broad categories:
- Services to send messages from a system to a person. Email is the focus, but only because I think developers have not considered possibilities beyond that.
- Message Queue: Broad category but the specific here is the ability for an application to send a message or document to another.
- Service Redirect: Having the appearance of IS&T's web services hosted at one host, but just providing mapping or redirection to the existing service.
- Service Index: Another loaded term. In this context, a place where a human can look up our services and a place where an application can look up services.
Here is a link to notes about messaging plans in SAIS common services: Common Services Messaging Discussion
MAP Working Group meeting minutes on messaging and ESB
Mellon group ESB evaluation results.
There were a couple of useful Burton Group reports of recent vintage. They are most useful in thinking about which standards or protocols meet your requirements and thinking about ESB as a part of a wider SOA strategy.