They're almost certainly post-processed to some degree, but how much depends on the skill & experience of the photographer(s). In fact, taking shots like this is quite easy, ONCE you get the formula down pat. I would do this using four small speedlights and modifiers (18-24" Lastolite Ezy-box style softboxes would be my preferred modifer), radio triggers, a table and roll of white seamless paper.
Two lights are only for the background. They should be set to expose the background 1/2 - 1/3 above the exposure of the subject, the other two are going to be used, in conjuction with various pieces of white & black card stock to add and subtract light as required. One of the biggest mistakes people make when starting this kind of work is having their lights too far away. The closer the lights (with power output reduced appropriately of course), the softer and more manageable it is.
The book that Astro linked you to is an excellent reference and will walk you through this, step by step.