An X-rated video surfaced on the Web yesterday allegedly showing Lohan bending over her ex-boyfriend, Calum Best, and performing a sex act. It was supposedly captured on Best’s cell phone. Lohan is telling pals the woman in the film is absolutely not her - “But privately, nobody believes her. It is her,” one told us. A call and an e-mail to Lohan’s rep, Leslie Sloane Zelnik, were not returned. Best, bad-boy son of English soccer star George Best, has ...