This video shows a custom built R2D2 like LEGO Mindstorms NXT Robot controled via windows phone 7. A good friend of mine Dimitris-Ilias Gkanatsios helped me port a WPF app that I built to a WIndows Phone 7 controller for R2D2.
Credits for the Windows Phone 7 app go to Mr.Gkanatsios!!!
You can find a detailed post along with the code of both the WPF and Windows Phone app on