Serge Luca - who recently decided to make a move from Guidance to u2u - wrote an article on starting and killing a workflow with the Windows Workflow Foundation. This was published earlier today on www.msdn.be.
Here's the summary of the article:
The Windows Workflow Foundation is a programming model, a run-time engine, and a set of tools for building workflow functionality into .NET applications. Windows Workflow Foundation (WF) is a core component of the .NET Framework 3.0 and can be used on Windows Vista, Windows XP SP2 and Windows Server 2003SP1. In this article, we will focus on how to dynamically and asynchrounously start and stop a workflow from within another workflow. We will also take a look how to pass parameters to a workflow, create custom activities and finally we will have a quick look into the WorkflowRuntime Services. The code samples have been tested with the RTM version of the Microsoft .NET Framework 3.0.