The Waze app for Windows Phone includes most of the features you would expect like routing based on crowd-sourced real-time traffic and road alerts including accidents, hazards, police traps, road closures, etc. It will learn your frequent destinations, commuting times and preferred routes, and give show the cheapest gas while you're on your way. And, you can easily share of your ETA, expected delays, and let friends know when you arrive. As usual, this activity will help you to earn points and move up in your community leaderboard. And, of course the maps are all edited and updated by Waze community map editors.
One item to note is that neither the app description nor the official blog post about the app release mentions integration of Google Search in the app. That was a big part of the recent cross-pollination between Waze and Google, so it would be odd if it weren't in the app, but it isn't mentioned anywhere. Waze is available now for free on Windows Phone 8 devices.
Download: Waze (Windows Phone 8)