Everything regarding implemeting a custom UI is on the wiki:
http://www.intalio.org/confluence/pages/viewpage.action?pageId=1601
Look at the overview, pdf and clickable svg diagrams.
You can also look at the presentations I did at the user conference:
http://www.intalio.org/confluence/display/TEMPO/Presentations
This is mostly for tempo components though.
If you want to build a web administration console for processes in
ode, it would be better to ask on the apache ode mailing list. I can
help a bit, especially when it's related to tempo/workflow processes,
but for more details on the BPEL engine processes you should
definitely ask them.
Don't hesitate to ask questions!
Niko
Is this an easy way (API, Web service) to get the history of action
performed on a process?