The word "inauguration" means "a ceremony marking the beginning of something new". The Inauguration of a President refers to the ceremony, which gives the President of the United States the powers of his new office.
On Tuesday, January 20, 2009 at 12 noon Senator Barack Obama of Illinois will take his oath of office at the United States Capitol and be inaugurated the 44th President of the United States of America.
Like 43 men before him, Barack Obama will raise his hand and say:
I do solemnly swear (or affirm) that I will faithfully execute the office of President of the United States, and will to the best of my ability preserve, protect and defend the Constitution of the United States of America.
Article II Section I of the Constitution of the United States of America
After he takes the oath of office, the President gives a speech called the Inaugural Address. In this speech the new President describes his vision of what he wants America to be and his plan for how the country can achieve this.
Some Inaugural Addresses have become very famous, some have been very long (one and one-half hours), but all of them have been very important in letting the people know what our new President believes and plans to do.