For those of you that haven't seen it yet, check out the new core article on t-nation by Mike Robertson. It's wicked. I particularly liked his definition of the core being like a box with:
The diaphragm on the top
The pelvic floor on the bottom
The abdominals (rectus abdominus, TVA) in the front
The back muscles (spinal erectors, multifidi) in the back
The lateral stabilizers (quadratus lumborum, internal and external obliques) on the sides.
Good stuff, plus there's loads of exercises for people like me who HATE doing planks.
http://www.t-nation.com/free_online_art ... training_1