Answer is Don’t use empties.
Perfect Foot as follows:
Legbone_Null: Connected(not just parented) to the last leg bone, very short bone. You can select the knob at the end of the leg and extrude.
IK_Legbone: Put cursor to the base of the Legbone_Null(where the last leg bone and the Legbone_Null meet) and add this bone. Should be semi-long and sticking out the back of the foot so you can grab it when animating.
Foot_Bone: Start this one at the Legbone Null base and go to the base of the toes, and make 2 bones, the second one at the end short and called Toe_Null. Toe_Null must be connected(not just parented) to it. Just make the Null go sideways and out of the way.
Toe_Null: Read above.
Toe_Bone: Start this at the base of the Toe_Null(where Toe_Null and Foot_Bone meet) and extend it to the tips of the toes.
IK_Toe: Start this at the base of the Toe_Null(again) and run it straight up, make it as long as the Toe_Bone.
IK_Foot: Start this in the heel and go about into the arch of the foot with it. Should be roughly the same length as the Foot_Bone.
Make the IK_Legbone a child of IK_Foot.
Make the IK_Toe a child of the IK_Foot.
The Foot_Bone has no parent.
The IK_Foot has no parent.
The Toe_Bone has no parent.
Both Null’s are children of the bone’s they’re stuck to.
Toe_Bone : Copy location, OB - Armature(this same on all these constraints), BO - IK_Toe
Toe_Null: IK Solver, BO - IK_Toe
Foot_Bone: Copy Location, BO - Legbone_Null
Legbone_Null: IK Solver, BO - IK_Legbone
If you’ve never done constraint’s before, Select the armature, hit the smiley face or Cntrl+Tab. Go to the Constraints window, (Chain link icon)
Press add, then in the top left of the box is a drop down menu to select IK Solver and Copy Location and other stuff.
I assume you know how to connect mesh to the bones, only the Foot_Bone and the Toe_Bone should have any mesh attached to them.
Just grab the IK’s and go for it, in Pose mode.
Hope this helps!
Edit: Guess I should say that I learned this from looking at Blendo and folowwing this tute: http://blenderchar.weirdhat.com/foottute/