VIDEO REPORT: Six key speeches by Barack Obama

Barack Obama will give his most important speech on Tuesday, when he becomes the first African-American to become president of the United States, but it won't be the first important speech of Obama's political career. Here are six key speeches of Obama, from his 2004 keynote address at the Democratic National Convention, when he was an Illinois state legislator, to his victory speech Nov. 4, 2008, in Chicago's Grant Park.