And impressively, all without GPS. What you're seeing is cell tower data, stored locally on my laptop when i backup my phone. The software locates your phone's backup files & displays it's location history. Pretty creepy. And yeah, kinda beautiful at the same time.
Zooming in closer to San Fransico, you can see how accurate it is with all the tiny trails mapping hundreds of photo excusions.
if you're on a Mac, track yourself with iPhone Tracker: http://petewarden.github.com/iPhoneTracker/