I remember reading a forum post last week about getting smooth airbrush looking skin for portrait shots. I ran across this great tutorial at usefilm.com Looks pretty nice. Neat Image Portrait Tut
I've used this technique before, as I discovered long ago that you could use Neatimage in an unorthodox way to soften a portrait, or clouds in a landscape, etc. I think what is important is not to overdo it, as the portrait will look unnatural if you do. I will reduce the settings considerably, as to find a happy middle ground between softening and looking "fake".
Used in moderation this is a GREAT tool.
PS. I think I heard that there is a Photoshop plug in version of Neatimage available. Has anyone used it?
The NeatImage Pro version has a PhotoShop plugin mode. I have it installed, and that's the only way I use NeatImage anymore. It's not any faster of course, still achingly slow esp. on big files from my 10D (tried it on a 7-image panorama, could have gone for a cup 'o joe... or two!), but I do find that Neatimage is an indispensable tool in the digital darkroom, and thankfully DPC LEGAL.
That said, I don't use NeatImage to soften portraits. I use two (or three) gaussian blur layers with various radii, individually faded to get the desired effect. I also use a mask to keep eyes sharp. I find this to be a much more natural look than softening with NeatImage.
edit:
Of course if you have the plug-in version of NeatImage installed, you can perform the NeatImage softening, and then (must be immediately) select edit/fade NeatImage and adjust as needed. Still doesn't let you keep selective areas sharp, but it's DPC-legal!