Zens has a new Qi wireless charger, and this one is for your car. The aptly-named "ZENS Qi Wireless Car Charger" is set to hit markets on April 15th for an eye-melting €69.99 (US$96.54). It's designed to split into your cup holder and has a slot on its top designed to accommodate smartphones with displays up to 5 inches. Blessedly, the vast majority of phones that support Qi charging (both Android and Windows Phone) fall into that range.
As a car charger, it's powered by your car's 9-volt port, so you'll be loosing both that and a cup holder to charge up your phone wirelessly while on the go. On top of that, the design of Zens' car charger means that you're not going to be seeing your phone, so you'll only be able to get (likely muffled) audio directions from it if you use your smartphone for navigation.
If you're okay with such limitations, the Zens Qi Wireless Car Charger will probably suit your needs just fine. If you're not, there are other Qi chargers for automotive applications on the market, including the highly-rated Nokia CR-200 (check out Windows Phone Central's review here).