I found this a while back on Digg I think, it’s really neat!

Creating your own Planet style pictures from Panorama shots. Most compact cams have a panorama mode and even the newer phone cameras have the feature which allows you to easily stitch a few shots together.

Our pal Dirk wrote up a tutorial that shows you how to turn any panorama or landscape photograph into a full-fledged planet!

Best of all, once you’ve selected an image to work with, the process takes only 5 minutes. (Launching your new planet into solar orbit may take a bit longer.)

360 degree shot of San Francisco taken from the Coit Tower made into a planet.

Pretty neat eh?

You can find the full tutorial and examples here:

How to Create Your Own Planets Using Your Panoramas

There is also a big Flickr set of examples and a Flickr Group dedicated to this.