The device's function is simple: it's a special iPhone case (together with an UV filter and SLR adapter) to which you can attach a variety of photo lenses - telephoto, wide angle, macro or fixed-fifty - which should greatly increase the quality of photos taken with your phone.
It comes with certain caveats: for example, your images will be upside down, due to the fact that SLR cameras have a mirror inside them which flips the image right-side up - something that iPhone obviously doesn't have.
We're also sure that the entire thing will look like a gross overkill to many, but we can imagine a couple of uses for it: if nothing else, it'll surely make you a star at the next photo convention.
The iPhone 4 version of the mount costs $249, while the iPhone 3 variant will set you back $190.
For more iPhone photography-related accessories, check out this list.