The app was built using Google App Engine in Python and Sencha Touch framework. If you're using Chrome or on a touch-enabled device, you can view the app here
The app uses the WeatherBug JSON API for weather feed and Google Maps for reverse geo lookups. It has screen screens (shown below) and a form that allows you to enter location information (state, city, zip). The location data is stored in App Engine's DataStore. All source (js and python) is available on the GitHub.
View this site on your device to experience the AppGet Source