What does the Internet look like? How does it evolve? The DIMES project aims to collect data to answer these questions by mapping the structure and topology of the internet. It is a distributed scientific project with thousands of participating volunteers. You can also join by downloading the DIMES gent here.
Chris Harrison has spectacular maps based on the data collected by the DIMES project. The Internet Map shows connection density and city-to-city connections. It is also available in high resolution PNG.