I don't know exact steps w/Photoshop but I imagine it's done using polar coordinate and swirl filters, or something like that - ones that come with PS or ones people download. There's probably several ways to get it done, some better than others, some more 'shortcut-y' and some more pro.
This isn't exactly what you want, but it might give you a clue on one or two ways to do things. Tons of tutorials out there, google the swirl.
http://www.thedesignworld.com/photoshop-tu...n-swirl-effect/
http://www.tutorialwiz.com/wallpaper2/