Oprah Winfrey will be calling it quits on her hugely successful talk show in 2011 after 25 seasons on air. Harpo Productions Inc says the talk show queen will explain the reasons behind her decision live on The Oprah Winfrey Show today. Winfrey started her broadcasting career in Nashville, Tennessee, and Baltimore, Maryland, before relocating to Chicago in 1984 to host WLS-TV's morning talk show AM Chicago. That show was renamed The Oprah Winfrey Show in 1985. The Oprah Winfrey Show is broadcast from Chicago on ABC across the United States and on various channels worldwide. It is one of the TV industry's biggest money-makers and is the top-rated US daytime talk show, avergaing 7.1 million viewers this year. Winfrey, 55, is regarded as one of the most influential people in America and this year was number 45 on Forbes magazine's list of the world's most powerful people. Her last show will air on September 9, 2011.<br/> <br/>