That camera looks a little precarious, and I'm not sure how much I want to depend on my pants to hold something up, but I can see how a DSLR belt holster might be useful.
As far as design goes, it's simple and smart: the holster fastens to your belt like any other dad-clip, and latches onto cameras by the tripod mount. Carrying a camera around this way could be a bit rough on both your leg and your lens, but as a way to temporarily free up your hands it's more liberating than a dangly neck strap. Shipping this summer. [CNET via Engadget]