Some Windows Workflow resources

WF Developer Center on MSDN – it all starts with the MSDN Dev Center
WF Community Site – tons of samples, walkthroughs, activities, and more!
WF in the .NET Framework 3.0 SDK – WF SDK reference
Cutting Edge: Windows Workflow Foundation, Part 1 – Dino Esposito does it again, with a great article on WF
Cutting Edge: Windows Workflow Foundation, Part 2 – continuation of exploration of WF

Thanks to Ron for links.....

Performance Characteristics of Windows Workflow Foundation

The performance of a WF application depends on many different factors, including persistence pattern, activity complexity, tracking usage, and so on.

Marc Mezquita discusses more in his GREAT article "Performance Characteristics of Windows Workflow Foundation"

Hosting Windows Workflow Foundation

WF provides a runtime engine and services to execute workflows and manage their state. A host application or a process must be written to host WF workflows. This host application is responsible for providing various runtime services to the workflow runtime engine.

Moustafa Khalil Ahmed Program Manager at Microsoft Corporation discusses on Introduction to Hosting Windows Workflow Foundation.

On the orther hand Vihang Dalal discusses here on Re-Hosting the Workflow Designer.

Getting Started with Microsoft Windows Workflow Foundation

A Developer Walkthrough by Dino Esposito on Getting Started with Microsoft Windows Workflow Foundation. Cool article discusses how to create simple WF application.