You are invited to get download the YAWL workflow system.

YAWL (Yet Another Workflow Language) is a workflow language/management
system based on Petri nets and a rigorous analysis of existing
workflow management systems and workflow languages. Unlike traditional
systems it provides direct support for all of the workflow patterns
(http://www.workflowpatterns.com).

YAWL supports complex control-flow process designs in a simple,
intuitive manner.   It allows for the design/use of complex data
models inside processes.   Furthermore it is able to exploit state of
the art Web technologies such as WSDL.

It contains an easy to use GUI Editor to create process models, and of
course YAWL is built using Java!

Project: http://www.citi.qut.edu.au/yawl
Documentation: http://www.citi.qut.edu.au/yawl/yawldocs.jsp
Download: http://www.citi.qut.edu.au/yawl/downloads/download.jsp

YAWL is an open source initiative and the key people are:
   Arthur ter Hofstede http://sky.fit.qut.edu.au/~terhofst/
   Wil van der Aalst http://is.tm.tue.nl/staff/wvdaalst/
   Lachlan Aldred http://sky.fit.qut.edu.au/~aldredl/
   Marlon Dumas http://sky.fit.qut.edu.au/~dumas/
   Lindsay Bradford
http://www.citi.qut.edu.au/people/student_pages/bradford_l/index.html