East African leaders will attend the signing in the Kenyan capital, Nairobi, joined by outgoing US Secretary of State Colin Powell.
The war has pitted the Muslim north against Christians and animists in the south, leaving some 1.5m people dead.
The peace deal does not cover the separate, newer conflict in Darfur.
United Nations Secretary General Kofi Annan has warned of worsening violence in Darfur, in the west of the country, where government-backed militia are accused of killing thousands as part of a campaign against rebels demanding more rights.
FINAL PEACE DEAL
- Both sides will unify into 39,000-strong force if the south does not secede after six years
- The south will have autonomy for six years followed by referendum for secession
- To be shared 50:50
- To be split 70:30 in favour of the government in the central administration
- To be split 55:45 in favour of the government in Abyei, Blue Nile State and the Nuba mountains
- To remain in the north
- Sharia in Khartoum to be decided by elected assembly
On the eve of the southern peace deal, the main rebel leader, John Garang, said he hoped to join peace talks on Darfur once he joins the planned national unity government.
"If I am invited I will come. If I am not invited I will ask to be invited," said Mr Garang, leader of the Sudan People's Liberation Army (SPLA).
Mr Garang, set to become a vice-president, will sign Sunday's peace deal with President Omar al-Bashir's government.
Starting in July, the south will be autonomous for six years and will then vote in a referendum to decide whether to remain part of Sudan, or become independent.
Sudan's new oil wealth - currently producing about 320,000 barrels a day - is to be split equally between north and south.
Apart from an 11-year period from 1972-1983, southern Sudan has been at war continuously since 1956. Peace talks began in 2002.
In 1983, the government dominated by northern Arabs tried to impose Islamic Sharia law across Sudan, even in areas where the majority is not Muslim.
The peace deal being signed in Nairobi follows the signing of a permanent ceasefire on New Year's Eve.
Published: 2005/01/08 16:00:44 GMT
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