This page and pages like it should be moved to http://profiles.tiki.org since it's about how to configure various features to solve a use case. Please see where.
What is a workflow?
Entity-based vs Activity-based workflows:
http://wiki.zope.org/zope3/TryingToUnifiyWorkflowConcepts
For Activity-based workflows, Tiki offers Galaxia Workflow. But this overkill for entity-based workflows.
One possibility is to use Wiki Page Staging and Approval.
The other is to setup your document workflow using Wiki pages, and have various groups Watching the categories. A tutorial would be nice here.
Profile: Document_Workflow
Dev: Approval Workflow