This action has become a popular alternative to Portraiture. It works by smoothing the surface of the skin without smearing it, then it gives you control of the intensity of that smoothing.
This works on full size 300 dpi images. If you are working with layers, make sure you are on the top layer. It copies and merges all layers to a new layer (leaving your original layers intact), then sets the smoothing layer. If you have adjustment layers you can hide them all then highlight the top pixel/regular layer, run the action, then turn your adjustment layers back on.
Important: Brush over the areas you want to smooth with a soft white brush. Change the size to get into the smaller areas and adjust the opacity of the layer to change the level of smoothing.