Here are some great resources to get you started.

  1. Intro the WF4 Hands On Lab
  2. Introduction to State Machine Hands On Lab
  3. Intro to Workflow Services / AppFabric Hands On Lab (Part of the Visual Studio 2010 Training Kit)
  4. Check out the Contoso HR Workflow Services Sample
  5. endpoint.tv – countless episodes of video goodness
  6. WF/WCF/AppFabric samples on MSDN Code Gallery
  7. WF4 Samples on MSDN Code Gallery
  8. WF4 Developer Center on MSDN
  9. WF on CodePlex at http://wf.codeplex.com with great tools and utilities