William Kious wrote:
Pretty much anything you can thin down to the consistency of milk can be applied with an airbrush.  If you're thinking about trying something on the cheap, tempera can give some really neat effects.  I've heard of some people using acrylics with some success, but I think it would be the devil to wash off.  I wouldn't advise using artist's water colors, though (they can stain skin like crazy.)

AAAAAAAAAAAAAAGHHH!

No paint!

Makeup makeup makeup. William is right in that airbrushing is possible with anything properly thinned but please do not use paint. Remember, these ladies and men make a living with their skin and it should be treated with appropriate concern. You wouldn't want someone cleaning your lenses with their Levi's would you?

Cosmetics should be used on skin. In the U.S. anything sold as a cosmetic must use only ingredients approved by the FDA for use on skin. It protects the model from stains and poisons, it protects you from lawsuits and really pissed off models.

The bodypaint post on the other forum will help...but here...I'll help too

IF you want to paint on skin look up...Mehron, Ben Nye, Snazaroo, Kryolon, Fardel, Temptu, Dinair, Graftobian, or Fantasy Faces.

If you want to use latex, look up Deviant.

Greasepaint is relatively safe, but generally messy and difficult to clean without the proper skinsafe solvent. Waterbased makeup is generally much easier to deal with and durable enough for the average shoot.

Of course...another alternative is to hire a professional who knows all this stuff already.