How do I remove these screws from an IKEA Micke table?
Those don't actually screw in.  They just press in the hole and then tighten to the connecting bolt attached to the  opposing piece of wood.  Just loosen the cam so you pull the connecting bolt out.  Should be fairly easy.  

After that, if you still need to get the cam part of the fastener out, it should just fall out.  If it doesn't, I just stick a small screwdriver in the connecting bolt hole and lift it up.