Senator Barack Obama by Jemal Countess/WireImage.com, Oprah Winfrey by Jamie McCarthy/WireImage.com Senator Barack Obama by Jemal Countess/WireImage.com, Oprah Winfrey by Jamie McCarthy/WireImage.com

Oprah Winfrey on Saturday arrives in Iowa to stump for Barack Obama in two separate rallies, and then takes her "Endorsement Tour 2008" to New Hampshire and South Carolina (where the rally needed to be moved from an 18,000-seat arena to an 80,000-seat stadium). Though Obama's campaign manager promises "No free cars" for those who turn out, he hopes that Oprah-mania can be used "as an organizing tool [and] to reward people who have been working hard for us... and bring in people who haven't voted before."

According to the New York Daily News, Obama doesn't expect people to vote for him just because of the O factor, acknowledging that, "Ultimately, I'm going to have to make the sale."