No iffy third-party apps, no feature phone mobile version, Google's web-based Map service is back on Windows Phone devices. We just went down to the Nokia bus here at CES to give it a try, and it's working as you might expect. While the smartphone screen isn't the best place for a desktop map site, pinch to zoom and scrolling worked and we were able to hunt down places of interest. The more mobile-centric Google Places also reappeared ready for use, if you prefer your maps ready for vertical displays.
[Thanks to everyone that sent this in]