Oprah Winfrey, move over. Regis can sell books, too. “Who Wants to Be a Millionaire” contestant Brad Herzog happened to mention on the air this week that he had written a book — “States of Mind,” a travelogue about small-town U.S. — and by the next day, the title leapt from No. 122,000 to No. 9 on the Amazon.com bestseller list. He also made $64,000 on the show.