Visual RPG for Visual Studio 2008 currently offers Beta WPF/WCF/WF support for .NET applications. The user interface is the part of your program that users see when they run the program; whereas Windows Presentation Foundation (WPF) applications are applications for which WPF controls are used to create the user interface. In these applications, the user interface usually consists of a main window or form and several controls, such as buttons and text boxes, etc. WPF uses a markup language called Extensible Application Markup Language (XAML) to provide new techniques for developing visually enhanced user interfaces.
Controls used in WPF applications are separate from Windows Form controls. However, they are added and modified in the same manner.
Since this is a Visual Studio functionality, please refer to the Visual Studio help topic Windows Presentation Foundation for further information.