Skin Tones
In digital photography most skin tone issues occur because the cameras in general adds a red hue or tint to flesh tones...And, if there is any issue with white balance, skin tones becomes an issue.
I found a really good tutorial that takes us beyond just correcting for a red hue/tint on Smug Mug's web site. For your convenience the Smug Mug Web Page is visible below on this page...Click on the window and scroll... url is http://www.smugmug.com/help/skin-tone
90% of all you need to know is that you can never let the yellow % fall below magenta % on anyone's skin unless you're trying to show sunburn.
Getting Great Prints: Pleasing Skin Tones
Here's a method for developing skin tone palettes Skin Tone Tutorial
and Adobe has a color tool called Kuler... It can be integrated into Photoshop CS5
Here's a video about Kuler from Adobe's web site