The 47-year-old first African-American to enter to the White House as the 44th President, Obama would be sworn in by the US Supreme Court Chief Justice John Roberts at 11:30 a.m on Tuesday (2200 IST) at the Capitol Hill.

Tens of thousands of people, braving severe cold, have started flocking to Washington from all over the country to be a witness to the historic occasion, when a black would become the US President. Estimate say that by the time Obama takes his oath the figure would swell to well over 2 million people.

His inauguration would take place outside US Capitol which slaves helped build.

"Tomorrow we will come together as one people on the same wall where Dr Martin Luther King dreams echo still," the President-elect said last night.

US Secret service and thousands of police personnel have thrown unprecedented security ring in a three square kilometer area where the event would take place. Sharp shooters in plain clothes have been deployed in the area.

The actual inaugural ceremony itself would begin at 11 am (2130 IST) on the West Front of the US Capitol with musical selections by the US States Marine Band, followed by the San Francisco Body Chorus and the San Francisco Girls Chorus.

The Democratic Senator from California Dianne Feinstein, in the capacity as the Joint Congressional Committee on Inaugural Ceremonies, would deliver the welcome address and call the function to order. This would be followed by invocation by Dr. Rick Warren.

Thereafter Joe Biden would be administered oath of office to Vice President by Supreme Court Associate Justice John Paul Stevens. Following musical selection by composer John Williams, the US Supreme Court Chief Justice would administer the oath of office of US Presidency to Obama.

The incoming First Lady will carry the Lincoln Bible to the platform and hold it while the oath of office is administered.

Obama is expected to deliver the Inaugural address at approximately 12 noon (2230 IST), which will set out the agenda of his government both within and outside the US.

The new President will then proceed to the Capitol where he will sign cabinet secretary nomination certificates.

The day for the incoming President and the Vice President would begin with a church service in the morning at St. John's Episcopal Church. From here they would head to towards the White House.

Earlier in the morning, the outgoing President George W Bush would welcome his successor Obama and his wife Michelle Obama at the North Portico of the White House some two hours before the swearing in ceremony.

Thereafter Bush along with his wife would have coffee with the incoming first family along with the Vice President-elect Biden and members of the Joint Congressional Committee.

It is at 10-45 a.m. (2115 IST) that Bush would depart the White House en route to the Capitol to participate in the swearing in ceremony.

In television interviews over the weekend and at his last press conference, Bush said he is looking forward to have Obama as the President.

Obama, who was a bitter critic of Bush during the election campaign days, now believes that his predecessor is a "good man". Obama told this to CNN in an interview. Soon after the inaugural ceremony is over, Obama would host a departure ceremony for Bush, who would leave for his new home in Midland Texas from the Andrews Air Force Base.

Obama and his deputy Biden would proceed towards the historic Statuary Hall at US Capitol for a luncheon hosted by Joint Congressional Committee on Inaugural Ceremonies. The inaugural parade would start at 2-30 pm (0100 IST Wednesday) from the US Capitol to White House.

The President and First Lady will travel with the Presidential Escort to the Presidential Reviewing Stand where they will meet up with their daughters and the Biden family to watch the rest of the parade.

Later, several dozen inaugural balls are scheduled for Obama with the Presidential Inaugural Committee itself hosting as many as ten inaugural balls including the Commander-in-Chief's Ball, the Youth Ball and the President Obama Home State Ball. Obama is expected to appear in the Commander-in-Chief's Ball at the National Building Museum.

Security for Obama's inauguration

An unprecedented security operation is under war in and around Washington for Barack Obama's inauguration as the United States' first black president on Tuesday.

Following are a few facts and figures about the steps being taken:

* The Homeland Security Department says there is no credible threat of an attack but they are prepared for a wide range of potential catastrophes, including a chemical weapons attack.

* The Secret Service, responsible for protecting the president, is overseeing the security preparations. Director Mark Sullivan, a 25-year veteran, says Tuesday's inauguration is the biggest event he has been part of.

* About 4,000 city police officers will be deployed along with 4,000 from 96 other law enforcement agencies across the country. Members of the Secret Service, FBI and Capitol Police will also be on duty.

* A total of 32,000 military personnel will be on duty or on standby.

* Security measures include intensified patrols of the skies over the capital and rivers bordering the city, closing bridges and sealing off a large area of downtown to vehicles.

* The Secret Service has unveiled a state-of-the-art armoured presidential limousine that Obama will use during his presidency. Its design is a closely guarded secret, but it is likely resistant to bomb and chemical attacks.

* Every one of the hundreds of thousands of people expected to pack the inaugural parade route between the White House and Capitol Hill will be subjected to security screening, as will the 240,000 people attending the swearing-in ceremony.