Trapster lets people with GPS-enabled phones document the exact location of a speed trap or red light camera. You can either run an application on your phone, access the mobile version of the site (trapster.com/m), or use in conjunction with Jott by speaking the details of the trap into the phone.

You can see my review of the Symbian version of the app, but they also have the application for Windows Mobile. The web or phone-based options for reporting don't get the benefit of GPS accuracy, either, but it's better than nothing.