I've heard about painting on fondant, what kind of "paints" do you use? Just your colorings or something different?

Luster/petal dusts thinned with vodka or lemon juice works. I've also painted on fondant using watered down Wilton pastes. It will look watered down though...not opaque. Here's some I painted with watered down green and black Wilton pastes. It's the head and tail for a turtle cake.

Some people use thinned down icing. Others use watered down food colorings. You can also use luster dust and wilton sells edible food markers. I have some, but have yet to use them.

Thanks for the tips, I'm hoping to get some luster dusts soon. How much liquid do you mix w/ the powder?

It depends on how intense you want the color and what you're painting on. There's some good info here at the bottom of the page...

http://www.sugarcraft.com/catalog/coloring/dusts.htm#info

In the attached picture, I used the wilton colors, mixed with a little clear vanilla. It worked great. Initially, I tried the Wilton food-color markers, and ended up returning them to the store. The book, paste jar and scissors are done with the clear vanilla/paste color.