Windows Workflow Foundation (WF4) in .NET 4 is designed to make it easier for new developers to learn, addresses wider range of customer scenarios, and is more efficient.
Design your Workflow: Visual Studio 2010 represents significant update to WF design experience. New designer's productivity enhancements for authors composing large workflows, including ability to expand & collapse child activities, breadcrumb trail along the top of the designer allows to drill in and out of deep workflows, and better visualization capabilities to discover and address validation errors.
Introducing Flowchart: WF4 introduces a flowchart style of control flow, which allows to create flexible workflows that require ability to loop back to previous steps, as well as skip steps based on conditions within the workflow.
Simplified Activity Model: WF4 dramatically reduces amount of code developers need to write to implement custom app logic for variety of scenarios. As activity model has been simplified, performance of runtime has dramatically increased.
Building a Workflow to retrieve the syndication feeds from a number of blogs.
Workflows and WCF Services: In .NET 4, we set out to make it easy to use workflows with services to compose and coordinate messaging by integrating WF with Windows Communication Foundation.
More info: WF MSDN Dev Center | The Workflow Way: Understanding Windows Workflow Foundation (white paper)