Sher Mohammad, 23, was among many supporters who trekked hundreds of miles to reach Bhutto's hometown of Garhi Khuda Bakhsh in southern Pakistan where she is buried.
"She gave her life for the people of this country, so we can walk a few miles to pay homage to her dignity," said Mohammad, whose feet were swollen from the trip.
On Saturday, Bhutto's widower, Pakistani President Asif Ali Zardari, is scheduled to speak in Garhi Khuda Bakhsh.
Bhutto was killed as she was leaving a rally in the garrison town of Rawalpindi, just outside the capital of Islamabad, where she was campaigning to return her Pakistan People's Party to power in parliamentary elections.
Her assassination shocked the world, fanning revulsion at rising militant violence in Pakistan as well as conspiracy theories that the country's powerful spy agencies were involved.
The government at the time, led by President Pervez Musharraf, blamed Baitullah Mehsud, a Pakistani militant commander with reported links to al-Qaida, citing a communications intercept in which Mehsud allegedly congratulated some of his henchmen. A Mehsud spokesman has denied any involvement.
Musharraf's government said Bhutto died from the force of the blast and not a gunshot wound, but many of Pakistan's 160 million people, already skeptical of Musharraf, questioned that account. Bhutto's party demanded a U.N. probe, and her widower Zardari, who became president after parliamentary elections in February, lobbied for one as well.
The U.N. chief assured the Pakistani people and government he was committed to search for truth and justice. He agreed to Pakistan's request for a U.N.-authorized independent probe into Bhutto's killing after a meeting in July with Pakistan's Foreign Minister Shah Mahmood Qureshi.
U.N. deputy spokeswoman Marie Okabe said Friday that the U.N. Secretariat "has been in consultations with the government of Pakistan to determine the nature of the commission, the scope of its mandate and the modalities for its establishment."
The Security Council, the U.N.'s most powerful body, must authorize any investigating commission.
"The secretary-general is hopeful that, with the progression of the discussions, the commission could be established in the near future," Okabe said.
Associated Press reporter Edith M. Lederer contributed to this report from the United Nations.