Just for the info, you might not need the script at all, as Autodesk added this feature in Maya 2011 (maybe 2010, not sure). Edit Mesh > Detach Component now splits edges like the Split button in Max (doesn't completely break the vertex like it used to).
Krynn> Be aware that this would require some form of vertex merge as well, else all verts associated along that edge would be detached from each other. I'm with Chronic's suggestion to use extract. If you don't want extract to create a new object of your selected faces then just uncheck the "separate extracted faces".