I have been doing a little reading on Flow Based Programming over the last few days. There is a wiki which provides further detail. And wikipedia has a good overview on it
This is what MQ Series, MSMQ and JMS are for.
This is cornerstone of Web Services and Enterprise Service Bus implementations.
Products like TIBCO and Sun's JCAPS are basically flow-based without using this particular buzz-word.
Most of the work of the application is done with small modules that pass messages through a processing network.