Freefluo is a workflow orchestration tool for web services initially developed by IT Innovation but now available to all from the Freefluo Sourceforge Site. It can handle WSDL based web service invocation. It supports two XML workflow languages, one based on IBMs WSFL and another named XScufl that is under development as part of the Taverna Sourceforge project.
Freefluo is very flexible, at its core is a reusable orchestration framework that is not tied to any workflow language or execution architecture. Freefluo includes extension libraries that enable execution of workflows written in a subset of WSFL. Support exists for for discovery via standard UDDI and recording of provenance.