Steelers offensive line coach Larry Zierlein apologized Thursday for accidentally e-mailing an explicit sex video to numerous NFL employees, including league commissioner Roger Goodell. Zierlein said the incident has been difficult for him and his family and that he intends to use his team-issued computer only for football business from now on. He sent a note of apology to all NFL employees and those with the Steelers who received his raunchy e-mail.