You can now download the final version of the .Net Framework 3.0 from here:

This includes WCF (Windows Communication Foundation, Indigo), WF (Windows Workflow Foundation) and WPF (Windows Presentation Foundation, Avalon). WF contains the Rules SDK and the Rules authoring environment for you to build on! It's been a wonderful journey for a lot of us on the product team and we're ecstatic to get this release out the door and in your hands.