The U. S. State Department report on human rights in Iraq, published in February 2004 and available at http://www.state.gov/g/drl/rls/hrrpt/2003/27928.htm, gives an estimate of 300,00 bodies found in mass graves. The report notes that not all mass graves have been investigated yet, and this number is a prediction for what will be found. The report also explains that "By the end of the year (2003), 275 mass graves had been reported to the CPA and 55 of these mass graves had been confirmed." This report talks about the 5 major events in which those found in mass graves had been killed, and also about numbers of disappeared people, many of whom ended up in the mass graves.

Human Rights Watch has a series of papers related to this issue as well, available at http://www.hrw.org/reports/2003/iraq0503/. This report states, "Human Rights Watch estimates that as many as 290,000 Iraqis have been "disappeared" by the Iraqi government over the past two decades. Many of these "disappeared" are those whose remains are now being unearthed in mass graves all over Iraq."

A group called Archaeologists for Human Rights, which formed specifically to deal with the excavation of Iraqi mass graves, has a document on their website (http://afhr.org/download/english.pdf) that lists all the graves that have been found, with citations to the news articles that announced these findings.

The U.N. report, "Situation of human rights in Iraq" (March 19, 2004) has the same information as the State Department on the number of confirmed mass graves, but does not list a number of people. (The direct link to this report doesn't seem to work, but you can search the UN Document Catalog (http://unbisnet.un.org/) for it.