Well, I have started a project of a Cocoa GUI for the Greycstoration command line programm.
Greycstoration is an Opensource Noise Reduction software written in C++.
For now, the GUI is only calling the command line version.
In my roadmap, I hope to include directly the library in the GUI, and make an Aperture-edit plugin.

Here is the obligatory screenshot :

Now some crop of the result when run :

800 iso crop greycstoration

If you would like to make a try you can download the binaries :

For those of you who wants to recompile it, here are the