SERIAL MOM. Kathleen Turner plays Beverly, the seemingly perfect, cheerful housewife and Mom (who also happens to be a foul-mouthed serial killer on the side), in John Waters's consistently sharp, amusing satire "Serial Mom." As far as plot structure goes, "Serial Mom" isn't all that impressive, but Turner's sheer comic energy as she kills typical suburban people for stealing parking spaces and not rewinding their rented videos carries this one quite a ways. Rated R. ***1/2 out of ****