iA's Web Trend Map 2007

2007's biggest websites depicted as a subway map, complete with weather outlook at each station. Go to the original clickable version on iA's site

Periodic table of the internet

The major sites of the internet organized into a periodic table. Source: wellingtongrey.net via infosthetics.com

Map of the internet universe

Jonathan Harris' Universe hardly could be called a map...it is a web geography interactive playland. Watch his talk introducing the project on Ted.

XKCD comic

A very clever map of online communities. Source: xkcd.com via infosthetics.com

Internet as logo collection

This is also not a map and has a cluttered feel, but does a good job of organizing top websites by category. Source: allmyfaves.com via infosthetics.com

The internet represented as a globe

Of hundreds of globes on display at Worldprocessor.com (fantastic website), two depict the internet.

iA's 2006 ratings for websites

Not a map, but a useful visual reference comparing popular sites across a number of criteria. They also rate news services, social networks, social linklists, corporate websites, and blogs. Check out the full page on iA.

World Map of Social Networks

This map by Valleywag shows the dominant social networking service in major countries.

Polish Map of the Internet

I can't read much of it, but it I can pick out the lands of 'Blogerra, Wikia, and Fotocz.'
From a Polish website.

First map of the internet?

This is as sketch of the first node on ARPANET at UCLA September 2, 1969. From Peter Salus' book "Casting the Net: From ARPANET to INTERNET and Beyond"