Here are some great resources to get you started.
- Intro the WF4 Hands On Lab
- Intro to Workflow Services / AppFabric Hands On Lab (Part of the Visual Studio 2010 Training Kit)
- endpoint.tv – countless episodes of video goodness
- WF/WCF/AppFabric samples on MSDN Code Gallery
- WF4 Samples on MSDN Code Gallery
- WF4 Developer Center on MSDN