The user generated GPS program Waze is coming to to Windows Mobile and Symbian. I have been using the Israeli version for a while now and I am a big fan. The software allows you to report on traffic jams, police presence etc as well as provide navigation services. They already have an iPhone and Android app and they are opening the alpha for Windows Mobile and Symbian and are looking for a alpha testers so sign up here if you need some help beating traffic http://www.waze.com/alpha_register/
For our Israeli readers, here is the link for the Hebrew version http://www.waze.co.il/
Take a look at the demo below: