A guy that used to be here at work, and some friends of his, have recently started up a website, showcasing their hi-res gigapixel images: http://www.xrez.com

It uses the google maps API for zooming in/out, and navigation around a photo, and there are some pretty good details on how their shooting process.

It would have been nice to have this rig over Thanksgiving, while I was at the Grand Canyon.