WASHINGTON D.C. | Expected to formally announce his presidential candidacy today, U.S. Sen. Barack Obama, D-Ill., is sure to be greeted by a large group of supporters in Springfield.

And the junior senator from Illinois hasn't just been in the news -- he's been in the spotlight. From Washington to Hollywood, admirers and critics alike have made him the talk of Washington.

In anticipation of his announcement, The Times offers answers to some FAQs on this widely-watched politician.

What is Sen. Obama's legislative background?

Obama began his political career a decade ago when he ran for Illinois State Senate in 1996. After serving two terms, Obama was elected to the U.S. Senate in 2004.

On a national level, he has been a leader in ethics reform and has pushed for energy legislation and increasing the minimum wage. He also has been an outspoken critic of the Iraq war since his years in the state senate -- an issue likely to be central to his campaign.

What were Obama's considerations in reaching a decision on a national candidacy?

Obama, who is married and has two school-age daughters, previously said that one of the factors going into his decision was the safety of his family. He also said the war in Iraq, which was a factor in his running for the U.S. Senate, was an influence on his thinking.

In announcing the formation of a an exploratory committee, however, he said an overriding factor was a desire for change.

"I've been struck by how hungry we all are for a different kind of politics," Obama said. "Many of you have shared with me your stories about skyrocketing health care bills, the pensions you've lost and your struggle to pay for college for your kids."

What are Obama's biggest strengths?

As a young, charismatic senator, Obama has a strong youth appeal that may cross conventional liberal/conservative boundaries. His idealism connects with many like-minded young people. Obama is widely popular on social networking web sites, such as MySpace, where there is a coalition called "One Million Strong for Obama" seeking to secure support for from a million youthful voters.

Another plus, according to experts is that Obama, was not forced to vote on the resolution authorizing the invasion of Iraq. He was a state senator at the time. As a result, he does not carry the baggage of other candidates, such as Sen. Hillary Clinton, D-NY, who voted for the use of force.

What will be some of Obama's potential hurdles?

Because many of his opponents have established strong ties to the African American community, there have been questions among experts as to whether Obama can lock up the black vote.

Hillary Clinton boasts strong support in the black community as, does former U.S. Sen. John Edwards, who gained popularity through his fight against poverty and his attention to New Orleans.

A recent Washington Post-ABC News poll found that 60 percent of black voters would vote for Clinton over Obama.

Another difficulty Obama may face is his limited experience in national politics. Obama, 45, has served on Capitol Hill for just over two years and has very little international experience.

What kind of support does Obama have?

Obama carries with him much support from the entertainment industry. Calling him "my favorite senator," Oprah Winfrey has publicly pledged her support. Mayor Richard M. Daley of Chicago also said he backs a run by Obama.