The principle is basically the same as scanning (but the usual scanner needs more than 1/160 sec to scan a negative). I've read quite a lot about this method and the big guys use special rigs for the camera and light boards to place the negatives on. I set up a simple DIY arrangement with a carefully levelled plastic board (the same one as you've seen a couple of glasses on), lit from below by a speedlite. The camera was on tripod from above and also carefully levelled.
It takes some time to tweak a LR/ACR preset that gives a nice result, but then I just apply it to the whole batch. Some individual fine tuning and cropping is also required to get the final result.