EAU CLAIRE, Wis. (AP)  -- Democrat Barack Obama laid out one of his goals Sunday for the Democrats' four-day national convention in Denver, saying that he hopes voters will come away with a belief that he's one of them.

``I think what you'll conclude is, 'He's sort of like us,''' Obama told supporters at an outdoor barbecue here. It was part of an ongoing effort to address voters' lingering concerns about his exotic name and unusual family history.

``'He comes from a middle class background. He went to school on scholarships. He had to pay off student loans,'' Obama continued. ``'He and his wife had to worry about child care. They had to figure out how to start a college fund for their kids.'''

As voters struggle with a limping economy, home foreclosures and sky-high gas prices, Obama and Republican rival John McCain have sparred over the question of which candidate can relate best to the anxieties gripping many middle-class families.

Republicans have sought to depict Obama as an Ivy League-educated elitist. His uncommon background - the son of a white mother and black African father, raised in Hawaii and Indonesia - has been grist for the rumor mill, leading some voters to believe he is a Muslim or unpatriotic. In nearly every campaign appearance in the last week, the Illinois senator has made a point of bringing up and then tamping down those issues.

The Obama campaign, meanwhile, has begun running television ads ridiculing McCain for saying in a recent interview he was unsure of how many homes he owns. McCain's wife, Cindy, is a wealthy heiress to a large beer distribution company and the couple own several properties in Arizona, California and outside Washington.

Obama also took a sermon on humility to heart, predicting his presidential acceptance speech might not be the best at this week's Democratic convention despite his oratory skills.

``I'm still tooling around with my speech a little bit,'' Obama told reporters. ``May not be as good as the other headliners the first three nights, but hopefully it will make clear the choices the American people are going to face in November.''

Obama headed back to Chicago after the quick trip to this Midwest battleground state, planning to spend several more hours at a downtown hotel practicing the speech he will deliver Thursday night.

During his brief visit to Wisconsin, Obama attended a barbecue and worshipped at Eau Claire's First Lutheran Church, where Pastor John Kerr made no mention of the presidential contest or the candidate in his congregation. But he noted that the morning's first scripture reading, from Romans 12:1-8, counseled humility and warned that no one should become ``cocky'' just because they are a good singer or good public speaker.

Later, Obama told the press he couldn't wait to hear his wife's speech Monday night. He said he'd also seen a preview of the video tribute that would introduce her to the convention. ``It's extraordinary,'' he said.

While he was heaping praise on others, he said his conversations with running mate Joe Biden in the past couple days ``make me absolutely convinced he is the right man for the job.''

Obama joked he was running for president to have Secret Service protection for his daughters - 10-year old Malia and 7-year old Sasha - when they start dating.

Obama was scheduled to arrive in Denver late Wednesday after campaign stops in Iowa, Missouri and Montana.

Aides said Sunday that Obama spoke by telephone with former President Bill Clinton Thursday and erstwhile rival Hillary Rodham Clinton on Friday. Both Clintons have prominent speaking roles at the convention as Obama's campaign seeks to bring her supporters into the fold.