But will it be enough to compete with experienced heavy hitters?
Political insiders like Donna Brazile, former campaign manager for Al Gore's 2000 campaign and an ABC News consultant, wonder.
"Unless he's able to raise $50 million to $75 million by the end of 2007, he won't be seen as a serious contender. Hillary Clinton will be able to raise that overnight," Brazile told ABC News.
Beyond the excitement of Democrats and some in the media, it's not tough to discern a feeling of confusion on Capitol Hill.
The question one often hears may be fueled by some resentment and jealousy, sure, but it bears answering: Just who the hell is Barack Obama? And why on Earth should he be trusted in these dangerous times with the most powerful job on Earth?
His biography is part of his selling point: Born in Hawaii to a white mother from Kansas and an African father, Obama moved around a lot as a child. After college he became a community organizer. Then he went to Harvard Law School where he became the first black president of its esteemed law review.
Chicago businesswoman Valerie Jarrett has known Obama and his wife, Michelle, for more than 15 years.
"He's a wonderful listener. He's compassionate, and he's the kind of person where if you pick up the phone and your voice sounds a little funny, he knows it right away and says, 'What's going on with you?'" Jarrett said.
What's going on with Obama is a catapulting into the celebrity stratosphere -- Jay Leno, Monday Night Football, Oprah Winfrey.
It all seems pretty heady. Obama even made People magazine photographed in a bathing suit near spreads about Hollywood pinups Penelope Cruz and Hugh Jackman.
Jarrett said that Obama was embarrassed by the photo.
"He was mortified. … It was a wake-up call. They think they are enjoying a quiet family moment, and they weren't," Jarrett said. "So in a sense it's a message that this is what their life is going to be like, and he's decided that it's worth it."
Former Republican National Committee chairman Ed Gillespie does not know Obama, and disagrees with his politics. He admires his talent, though.
"He is a very good speaker. I saw him in Boston at the Democratic National Convention, and he did a very good job," Gillespie told ABC News. "He enjoys a pretty broad appeal."
But Gillespie notes what Obama himself has acknowledged: that right now he's in many ways a blank slate on which fans are projecting their views and their hopes, and that this popularity is unlikely to remain the more people find out about him.
"Right now I think there are a lot of moderate Democrats who assume he is a moderate and a lot of liberal Democrats who assume he is a liberal democrat," Gillespie said. "In the end, given his numbers somebody is going to be disappointed."
Democrats may be disappointed to learn that as a teenager Obama did cocaine, as he said in the "Nightline" interview.
"Well, when I was in high school, you know, I did a lot of stupid things," he said.
Democrats may not like what they hear about a questionable land deal Obama was involved in with a political operative, who has since been indicted on fraud charges.
He told "Nightline" he could have handled the deal better.
"We paid higher than the appraised value. But, you know, it's a situation where I missed, sort of, the potential appearance of impropriety, or at least the possibility that he was doing me a favor," he said.