An updated noise-reduction algorithm is the main change in v5.9 of Kodak's acquire software for Mac and Windows, released yesterday. The included Mac version Read Me notes that v3.0.14 firmware is required to fix an incompatibility with the Powerbook G3/400 and G3/500's built-in FireWire ports; that firmware update has not yet been posted. The Mac version Read Me also indicates that v2.3 of Apple's FireWire support files are required if your desktop Mac has a Kodak-supplied FireWire card installed, though v2.3 is not yet released. Also note that Canon has not yet officially approved the v5.9 revision for use with the D2000.
Update, 12:15 MT: If you've been following the noise reduction saga on this page over the past several days, please note that I have what I believe to be the final answer about v5.9's Noise Reduction feature. If you have v3.09 or later firmware in your Kodak/Canon pro digital camera you can expect good results with v5.9's Noise Reduction switched on. Earlier discussions with a senior Kodak engineer, as this feature was being developed, led me to believe that the function would work independent of firmware version, and as such the v5.9 testing I did included a range of firmware version photos.
Looking only at noisy v3.09 firmware frames, however, I can see that there is a discernible improvement over 5.8.2. As I write this, I've only had an opportunity to make two test prints from v5.9 processed,v3.09 firmware photos, but in both cases the results look good. For really, really noisy frames, Quantum Mechanic Pro 2.1 for Mac, using both its blue chrominance filter and despeckle luminance functions, will still hang onto more detail while removing more blue chrominance noise. But for slight to fairly noisy images, v5.9's Noise Reduction feature seems effective at knocking down enough blue chrominance noise and luminance pitting to ensure that the resulting photo looks good on the printed page.
Remember, the caveat is that you must have firmware v3.09 or later loaded in your camera at the time the photo was shot, or the results will not be as I've decribed above. If you haven't updated your camera's firmware, or have lots of older photos to process, Quantum Mechanic remains a must.