Valery Hronusov has been looking at publicly available data from the FCC (Federal Communications Commission) and has produced several Google Earth data layers based on this data. These include visualizations that note cell phone tower density (example above) and TV towers per state. Another interesting way to look at data. You can read more about Valery's work over at the Google Earth Blog...
Technorati Tags: Google Earth, data layers, valery hronusov