Bill Cowher will announce his resignation on Friday after 15 seasons as head coach, sources have told the Post-Gazette. Cowher and his wife, Kaye, are scheduled to fly to Pittsburgh this morning to attend a 1 p.m. news conference at the team's South Side facility and announce the decision that has been expected for several weeks, if not longer -- that he will resign, at age 49, to spend more time with his family. "You'll be hearing from me soon enough," Cowher said last night from his home in Raleigh, N.C., where he has spent the past three days. He declined any further comment.