Good tutorials on bone based animation

[REDDemon]

Does anyone found some good articles/tutorials aboun rigged animation and FK / IK? I'm stuck with some problem of Kinematics for doing some animation at C++ level. So i'm not required to model skinned models in blender or to rig them. I need to understand deeply how this happens at low level. When I have to apply multiple matrices to each vertex that's ok and the hardware do that for me. I miss all other things.. For example visualizing a bone and turn it to a matrix.