Rainmeter is a skinnable, customizable resource meter and widget system for your desktop. Omnimo is a custom skin for Rainmeter that emulates the tile system used in Windows Phone 7 Series. With it you can monitor your email, weather, calendars, PC systems and more, while acquainting yourself with the look of WP7S.
Lifehacker has the complete rundown on how to get started with Omnimo. Wouldn’t quite work for my icon-free, pen-centric setup, but I can see it rocking on a touch system.