Here are some samples and articles on Windows Workflow Foundation I've written.
- SqlTrackingQuery Sample
- A sample Windows Forms application showing the use of the SqlTrackingQuery class. Updated for the .NET FX 3.0 RC1 release.
- MSMQ Activities
- A sample set of WF activities to send and receive MSMQ messages from workflows. The lates version of the code can be found at http://github.com/tomasr/msmqactivities/