The prosecution will be headed by Ramsey Clark, the former US attorney-general, who sits on Saddam's defence team, according to one of the organisers.
The two-day event, set to open on Friday in the Egyptian capital, will be sponsored by the Cairo-based Federation of Arab Lawyers.
It will bring together international lawyers and human rights activists including Ahmed Ben Bella, the former Algerian president, and ex-Malaysian leader Mahathir Mohamad.
Ziad Khasawna, the federation's assistant secretary-general and once Saddam Hussein's chief lawyer, said Nelson Mandela, the former South African leader and anti-apartheid icon, had accepted an invitation to be the chief judge if his health allows him to travel.
Ben Bella and Mohamad are also part of a committee to ensure Saddam's trial is fair.
The witnesses include Hans Blix, the former UN chief weapons inspector who monitored Iraq's weapons programme under Saddam, and Giuliana Sgrena, the Italian journalist who was kidnapped in Iraq in February 2005 and released a month later.
Charges against Bush, Tony Blair, the British prime minister, and Ariel Sharon, the Israeli prime minister, include "crimes committed against civilians in Palestine and Iraq," Khasawna said. He said details would be unveiled at the event.
The trial is not legally binding, but it will be an "exhibition of popular opposition to the policies of those three leaders in the region and the extent of harm and damage they inflicted on civilians and countries by wars they waged and the oppression practiced in jails run by their forces," Khasawna said.
Nelson Mandela might attend the
trial if his health permits
Aljazeera.net asked Khasawna whether this incident could provoke Bush and Blair to respond in court?
"I do not think they can do anything but listen to what people are saying. Otherwise, they should prove they did not bomb Falluja with white phosphorous, or did not invade Iraq and destroy its infrastructure and more," he said.
Khasawna said a similar trial took place in Turkey some months ago.
He expects the incident will attract attention internationally.
"There will be extensive media coverage, and we hope it will reach a wide audience"
Federation of Arab Lawyers
"There will be extensive media coverage," he said.
Khasawna said he does not know if Saddam Hussein and or his defence knows about the project.
Saddam's lawyers and other international activists have long spoken of plans to convene the mock trial, saying the publicity will help expose their view that Saddam is innocent of war crimes and that Bush and Blair are aggressors because they invaded Iraq on the false pretext that the country possessed weapons of mass destruction. No such weapons were found.