Greg Mahlknecht has drawn a map of the undersea communications infrastructure around the world using Microsoft Bing. I’d say it is pretty good. It gives you a good visual idea how the continents are interconnected.
Head over to his site to browse around, zoom in and out etc… http://www.cablemap.info/
Routing-Bits 
I need to contact him. He is spot on almost everywhere in the world except my neck of the woods. We have 2 other undersea cables that he needs to add ;) Other than that is a most excellent source of info on the undersea cable systems.