Windows Phone Hacker has more information on this:
The application is relatively simple: download the ZIP that contains both the phone and desktop applications. Then, deploy the phone application, and enable Jaxbot’s dehydration hack. After that, connect your phone to your computer, run the desktop server, and enter your computer’s IP address. Voila, your computer will now display whatever content is displayed on your phone, and you can use a screen recorder of your choice from this point on.