I am looking for a workflow management developer kit.

We are developing J2EE business applications with browser-based clients and
we are looking for workflow management engines to incorporate with our applications.
If anyone can suggest or recommend a source...

Some examples we have come across include:
- BEA Integration (with Business Process Management)
- AltoWeb

Other we have heard of:
- Ultimus
- Wakesoft
- Drala
- Workflow Solution
- Workflow Software
- Smart Workflow Solution