Fortune Magazine's list of
America's 50 Most Powerful Women in Business
highlights the women who have a "secret weapon" in the business world.
Fortune ranks the women not on their salaries, but by their past successes
and ability to effect change in their companies. In 2008, PepsiCo Chairman and CEO Indra Nooyi topped the list, while Oprah Winfrey, chairwoman of Harpo, came in at No. 8.