The Obama campaign has fought for more than a year against several rumours circulating on the Internet and in conservative news outlets.
One rumour states that the Illinois senator is not a Christian but a Muslim.
The website, www.fightthesmears.com, stresses, "Senator Obama has never been a Muslim, was not raised as a Muslim, and is a committed Christian."
A photograph on the website shows Obama being sworn into the US Senate with his hand on a Bible and not on a Koran, as some rumours have stated.
Some blogs and conservative commentators have claimed that Obama's wife, Michelle, used the racially divisive term "whitey".
The website states, however, that Michelle has never spoken publicly at either of the two venues where she is alleged to have used the term.
It also uses a CNN profile of the Indonesian school Obama attended as a child to counter a rumour that it teaches a radical interpretation of Islam to its students.
Passages from Obama's books are also elaborated on to dispel rumours that he harbours racial resentment and there is a video of him leading the Pledge of Allegiance to put to bed rumours that he refuses to do so.
The website encourages Obama supporters to email the responses to others.
"The Obama campaign isn't going to let dishonest smears spread across the Internet unanswered," spokesman Tommy Vietor said. "It's not enough to just know the truth, we have to be proactive and fight back."
