What is WPF?

WPF stands for Windows Presentation Foundation and it is essentially a new API for creating a graphical user interfaces for the Windows platform. It provides a consistent programming model for building applications and provides a clear separation between the user interface and the business logic. WPF employs the use of 2D and 3D drawing, fixed and adaptive documents, advanced typography, vector graphics,raster graphics, animation, data binding, audio and video thanks to the presence of DirectX in one of the lower levels of its architecture. WPF comes pre-installed on Windows Vista and i based on .NET 3.0. Although like its predecessor, WinForms, it too incorporates the use of buttons, combo-boxes, list-boxes etc, instead of using a designer generated code file or a resource file as the source of a UI definition, it makes use of XAML (Extensible Application Markup Language) which is a unique way of including code in a mark up.

PS: I apologize if this answer seems inadequate for i answered only because of the statement : Even if you can't offer a complete answer, help us get things started

If you are interested in WPF, also check out the Silverlight which is a cross-browser, cross platform plugin, that provides rich web based content to your browser. Silverlight is basically the web implementation of WPF.