I just started messing around with PyMel in Maya 2011 today so I'm sure I'm doing something wrong but I can't figure it out.
In the code below the polyCut is applied to the center of the object and not at the origin like I want. It seems the cutPlaneCenter (pc) flag/argument is being ignored.
import pymel.core as pm
pm.polyCut( cd="X", pc=(0, 0, 0) )