How to Choose the Right Enterprise Service Bus
Gartner Magic Quadrant: ESB vendors 2012
After reading the above two sources, you might begin to think that the Oracle and IBM SOA solutions are overkill, too expensive, or requires too much vendor lock-in for your needs. If so, read on:
Apache Camel (Integration Framework) VS
Apache ServiceMix (OSGI Container) VS
NServiceBus + ServiceMatrix/ServiceInsight/ServicePulse
Low Cost SOA using Microsoft technologies
If you are a Microsoft-stack developer, then this paper is really easy to follow. If your SOA needs are simple then some of the solutions he mentions may be enough for your project. Although the paper covers the VETO service mediation pattern, you should also look up VETRO–the R (“Routing”) is important.