Lackadaisy Expressions by *tracyjb on deviantART for drawing. This remains one of the best depictions of expressive drawing I've seen. A really great tutorial on how to draw facial expressions, and especially wonderful if you need to draw cartoon animals.
Concept art is amazing! If you really get a good perspective on it, it is really just someone designing a good outline or two on a character that will later on be added onto in more designed and exact areas.