General Anatomy:
Proko
Posemaniacs
Andrew Loomis Books
Asahi.net (In japanese, for a english index go here)
Manga Materials (Japanese with english subtitles)

Books:
Anatomy for Sculptors - Uldis Zarins with Sandis Kondrats
Color and Light - James Gurney
Understanding Comics - Scott McCloud
Morpho: Anatomy for Artists