How can I lighten dark skin tones using PhotoShop?

I don't use PhotoShop anymore, but here's a link to a "skin tone retouching" tutorial:

Peachpit: Portrait Retouching with Photoshop 7 > Improving Skin Texture

... and a couple little answers:
How in photoshop do you make a person's skin perfect? (like in magazines?)? - Yahoo! Answers

Use the dodge tool at a low percentage.