It's existence is still not absolutely confirmed, but the Michelle Obama "rant" tape is being described with a fair amount of detail on the pro-Hillary website Hillbuzz.

The Michelle Obama Rant Tape was filmed between June 26th - July 1st 2004 in Chicago, IL at the Rainbow/PUSH Coalition Conference at Trinity United Church: specifically the Women's Event.

Michelle Obama appeared as a panelist alongside Mrs. Khadijah Farrakhan and Mrs. James Meeks. [....]

For about 30 minutes, Michelle Obama launched into a rant about the evils of America, and how America is to blame for the problems of Africa. Michelle personally blamed President Clinton for the deaths of millions of Africans and said America is responsible for the genocide of the Tutsis and other ethnic groups. She then launched into an attack on "whitey", and talked about solutions to black on black crime in the realm of diverting those actions onto white America. Her rant was fueled by the crowd: they reacted strongly to what she said, so she got more passionate and enraged, and that's when she completely loses it and says things that have made the mouths drop of everyone who's seen this.

The "tape" is a DVD that Trinity United sold on its website, and possibly offered free for download up until March 2008 when Trinity's site was scrubbed and the DVDs were no longer offered for sale.