Fans of the WB show “Jack & Jill,” or even just those who are willing to do some good, can log onto the Web site for and bid to win a walk-on role in an upcoming feature film starring the show’s co-stars, real-life couple Jaime Pressly and Simon Rex. The film, “Unleashed,” will also star Jon Voight and follows a young police detective who is paired with a pup in an attempt to solve the murder of the doggie’s Zen master. The auction closes on Monday, April 9 at 3 p.m. PT, with 100 percent of the winning bid going directly to benefit the Chabad’s Children of Chernobyl, a humanitarian medical relief project, whose objective is to improve the health of children affected by the Chernobyl nuclear disaster.