This Ruby on Rails application can draw upon a number of different interfaces (Twitter, FrontlineSMS, etc) for mapping data, and produces maps in Google maps or custom displays in real time. Users can sign up for the service with their SMS-enabled phones and submit map data which shows up live on the web interface. They can also do geographic searches for keywords. Geocoding via GeoKit is used to find lat/lon from SMS messages.

Read more about the project at WHOOZ.org

There are video tutorials available which walk through the writing of this code with (somewhat muffled) commentary. These are available at:

http://unterbahn.com/category/tutorials/