I'd say they probably used a combination of things: Illustrator, Photoshop, and perhaps a 3d program such as 3DSmax or Maya. Mostly Photoshop, it looks to me. You just take a some funky 3d images and some flat ones and combine them in Photoshop with a monochromatic color scheme, add some tiny crisp vector art and maybe some pixel textures. I'll make one and post it.
3d programs I know of:
3d Studio Max
I used to use an old one called Poser for figures
3DSmax is only on PC