I've been meaning to make one for a while now, lips are the simplest things in the world to paint but it's actually deceptively hard if you don't know what you're doing (and I don't really either, but... hopefully I know just about enough to pass on some wisdom). Meh, anyway, I used Photoshop CS but it should work with just about any painting software in the world.
Hmmm, sorry if some of the things on here isn't very clear, feel free to ask questions.
P.S I'll probably make a better one when I'm not feeling so lethargic.
for How to Paint Eyes
for Portrait Painting; i.e. everything from skin tone to hair to lighting