Some post-processing programs have a function for creating the appearance of softening skin. For example, Lightroom has an adjustment brush for softening skin by reducing the clarity setting (local contrast). Corel Paintshop Photo Pro X3 has a Skin Smoother function that can reduce the appearance of wrinkles.
Sometimes, I get better results with very aggressive luminance noise reduction, either by itself or sometimes together with the built-in skin softening functions. In programs that have layers, I create a separate layer so that I can apply the effect selectively with a layer mask.
Yes, noise reduction reduces the available detail but you know what? The subjects who benefit from skin softening (ahem) don't care for the additional detail, and would rather have the appearance of porcelain skin.
Here's a sample shot .... NOT! I don't have any intention of risking my life needlessly. :)