DEADLY DAMES: Bette Davis and Barbara Stanwyck both turned the part down, but Joan Crawford won her only Oscar as waitress-turned-restrateur Mildred Pierce, who goes to extreme lengths to protect ungrateful daughter Ann Blyth in Michael Curtiz’ dazzling 1945 thriller. Film Forum is showing it today through Sunday on a double feature with another classic James M. Cain adaptation – Billy Wilder’s “Double Indemnity,” with Stanwyck and Fred MacMurray – as the launch of a four- week series on “Essential Noir.” Film Forum, Varick and Houston streets; (212) 727-8110 or http://www.filmforum.org.