The app I really liked is called VanPark 2010, and overlays metered parking rates on top of a map of downtown Vancouver.
Lots of geeks abstractly advocate the power of open source and open data, but this seems to be a great example of how opening up data can help the average citizen. I requested a feature where the user enters an address, and the app highlights the cheapest parking within, say, 500 meters.
And can we take a moment to recognize the awesomeness of Bing Maps’ Birds eye view functionality. It truly is the eye of God.