Some things that have helped me get to this point recently:
Practical Light and Color by Jeremy Vickery (Gnomon dvd)
Color Theory: The Mechanics of Color with Richard Keyes (Gnomon dvd)
Force: Dynamic Life Drawing for Animators (Figure Drawing book. EXTREMELY helpful.. two chapters brought my figures to life.
Force: Character Design from Life Drawing (Second book in the series.. even more amazing.)
This ImagineFX tutorial from Issue #31 on the subject of colour!