Absolutely one of the coolest examples about WPF: Tim Sneath has signalled that two engineers from Microsoft Switzerland, Ronnie Saurenmann and Ruihua Jin, have put together this 90-page lab that starts at File / New Project and ends with a facsimile of the Outlook 2007 user interface.
You can find the lab manual here; the source project you'll need to complete the lab can be found here.
Lots of thanks to Tim for the tips and to the two guys for the wonderful (and well done) work. It's the first WPF application with sources available that targets the Winform world and the Office 2007 style.