WPF = Windows Presentation Foundation, this is a technology to make the gui of applications.

I would advice you start here:
http://msdn2.microsoft.com/en-us/beginner/bb964633.aspx (Visual Basic)
or
http://msdn2.microsoft.com/en-us/beginner/bb964631.aspx (C#)
or
http://msdn2.microsoft.com/en-us/beginner/bb964629.aspx (C++)

or choose yourself here:
http://msdn2.microsoft.com/en-us/beginner/bb308891.aspx