Mobile environmental monitoring

Goes both ways: In London you can receive air quality info by SMS. Or sensors embedded in mobiles can detect and send radiation or pollen levels. "Grassroots citizen science" work by Eric Paulos in Ghana attached sensors to taxi drivers' phones in Ghana to measure pollution levels. Details here.

See also Urban sensing: Out of the woods: "Services such as Google Earth have driven to nearly zero the cost of this visualization measured in terms of dollars, time-to-deploy, and technical sophistication required." (See an example of the scientific use of Google Earth here.)