Visual Studio 2008 Kicks Off: Figure 5: Design Forms and Write XAML in the WPF Editor.
The graphical WPF Editor (formerly known as "Cider") lets you add controls to Windows forms from the Toolbox, edit the XAML code for the form and its controls, and hook up UI events to handlers. You also can edit XAML for Silverlight elements. However, the WPF editor doesn't support high-end designer features and nuances, so you'll need a license for Expression Blend to take full advantage of WPF graphical capabilities.