Chris Pendleton wrote a nice article on the Virtual Earth Evangelist Blog about Harley-Davidson's use of Virtual Earth in their Ride Planner application.  The application allows you to view some great motorcycle rides across America.  User can also upload their own custom routes to share with others.  You can also view information about each route and rate them, in addition to finding Harley dealerships, hotels, and events near routes. For more details see:

Virtual Earth Innovation at Harley-Davidson

Harley-Davidson Ride Planner