From CBS News' Maria Gavrilovic:
DES MOINES, IOWA -- While the effect that Oprah will have on Barack Obama's presidential bid is still up for debate, her ability to draw a crowd is not. Despite the winter snow storm in Des Moines, people flooded Hy-Vee Hall to see the 'Queen of Talk.' According to campaign estimates, 18,000 people came to see the Obamas and Oprah.
Winfrey was introduced by Michelle Obama, who teased the audience, "Barack and Oprah couldn't make it tonight, I'm just going to sing to you!"
The audience stood up and roared when Oprah took the stage. She told the crowd, "So much as been said about what my jumping into this arena does or does not bring to the table of politics and I really don't know."
"Despite the speculation and the hype, I understand the difference between a book club and free refrigerators," Oprah said, "I understand the difference between that and this critical moment in our nation's history."
Oprah also told the audience this is the first time that she has been compelled to speak out for a political candidate. "I am not here for partisan beliefs," she said, "Over the years, I have voted for as many Republicans as I have Democrats."
Oprah called on the audience to "think" and to choose Obama as their candidate. For roughly ten minutes, she described what she thinks Obama will bring to the presidency. "I believe that Barack Obama will bring statesmanship to the White House," Oprah said, "I believe that he will lead with strength, conviction, honor and compassion."
Oprah is a tough act to follow, and Barack Obama was quick to acknowledge that. "You know you've got a pretty good show when I'm the third best speaker." He went on to thank Oprah for coming to Iowa.
"There's this woman with a funny name," Obama said, "Nobody would have thought that she would become somebody who moves an entire nation each and every day."
Obama said that he e-mailed Oprah on Friday night to talk about the event. "I said it looks like a lot of people are gonna come tomorrow, I guess you're pretty popular."
After thanking Oprah, Obama quickly reverted to his stump speech. He spoke about Washington corruption, health care, the Iraq war; themes that he talks about every day. However, the audience focused on the guest of honor. One woman yelled out that Oprah should be the vice president.
Obama said, "You want Oprah as vice president? That would be a demotion, you understand that."
The Obamas and Oprah are now headed to a rally in Cedar Rapids, where the campaign expects an audience of 10,000. Tomorrow they'll be in New Hampshire and South Carolina.