From AP via globeandmail.com:

Democrat Barack Obama's campaign said Thursday that Michelle Obama never used the word “whitey” in a speech from the church pulpit as it launched a Web site to debunk rumours about him and his wife.

The rumour that Michelle Obama railed against “whitey” in a diatribe at Chicago's Trinity United Church of Christ has circulated on conservative Republican blogs for weeks and was repeated by radio talk show host Rush Limbaugh. The rumour included claims of a videotape of the speech that would be used to bring down Mr. Obama's candidacy this fall.

“No such tape exists,” the campaign responds on the site, www.fightthesmears.com. “Michelle Obama has not spoken from the pulpit at Trinity and has not used that word.”

The site is a response to the realities of a brave new world, where information travels 24 hours a day on blogs and voters are increasingly turning to the Internet for information. It's a particular problem for Mr. Obama, a relative newcomer to national politics who is still unknown to many voters and has been the target of persistent misinformation campaigns online.