NPR : Tailor-Made Cartography with Google Maps

All Things Considered, January 12, 2006 · Google's popular mapping service has inspired people to add their own information to maps. The resulting "mashups" are maps overlaid with clickable icons that provide a unique look at fast-food restaurant locations, crime statistics and other data sets.
Robert Siegel talks to Mike Pegg, whose Google Maps Mania Web log tracks the latest mashups, by category.
Topics include transit (Boston subway stations), current events (BBC world news), and weather and Earth (meteor impact sites).
Some are clearly designed to be useful for everyday life: New York pizza places, Washington, D.C., home prices, and Chicago crime locations. Others are more for fun: find the nearest pub or brewery, peek in on Webcams, or look for a convenient jogging route.
"One of my favorites is a mashup in Dublin, Ireland, which takes the real-time locations of a commuter train and plots it onto the map, and it actually shows that train moving," Pegg says.
Another popular mashup lets users see where they would end up if they drilled through the Earth to the other side. For example, click on Wichita, Kan., and you come out in the middle of the Indian Ocean.
"I think we're destined to see big things from this, both as the maps improve and as people's imaginations just continue to go wild with this," Pegg says.