This mashup of the Google Maps API and the Shizzow API can help you find the best espresso anywhere in the US. For each town listed the Espresso Finder shows a Google Map of all the places tagged coffee in Shizzow.
The front page of Espresso Finder contains a list of cities. Each city listed has its own Google Map. It is possible to add a location to any of the maps by adding a place to Shizzow and tagging it #espresso.
Google Maps mashups that help you find the nearest place to buy coffee are always popular. CoffeeSeeker maps all coffee shops within five miles of a search location.
One nice feature of the map is that the coffee shops are marked on the map with coffee cups bearing the logo of the mapped shop. Registered users can add their favourite coffee shops to the map, they can rate coffee shops and or add comments.