Really nice website with all the muscle name on a 3D model. Tutorial on muscle, anatomy and physiology.
For the muscle part:
Superficial Muscles of the Leg
Some muscle are not there, like the major muscle of the knee, bit sad but whatever. I think it's quite nice for learning or to know where the hell is the lliopsoas.
anatomy&physiology part:
Human Biodyssey: Exploring Anatomy & Physiology
It looks like a university website, I guess the information are acurate.