"It's important to acknowledge we have a debt that must be paid, a debt yet to be settled," said Interior Secretary Santiago Creel at the signing. "This agreement is the instrument that should enable us to meet that obligation."
The multifaceted pledge signed Tuesday night contains a provision for guaranteeing transparency, security and privacy in the exercise of the vote.
It also guarantees a voting system outside the country similar to that inside Mexico and contemplates a future need for a voter registration campaign abroad.
The Federal Electoral Institute (IFE) will be assigned to facilitate the 2006 vote in accordance with Mexican law.
The decision implies settling "a debt with those who, out of necessity... have had to emigrate across the border to other parts of the world to work, live and seek sustenance for themselves and their people, their families," Creel said.
"We'll do everything in our power so this becomes a reality as soon as possible," he added.
The pact was signed by representatives of parties holding seats in the lower house of Congress during a ceremony late Tuesday night.
Paoli Bolio, an Interior Secretariat official, said the agreement was the result of months of work, and added that there was no deadline for the law to go into effect.
He noted that 14 bills had been languishing in Congress and that none had passed due to "a lack of consensus."
"Without this step, it seems unlikely that a new bill would be approved, especially one all the parties could agree on," Bolio added.
Representatives of the Institutional Revolutionary Party (PRI), the ruling National Action Party (PAN), the Party of the Democratic Revolution (PRD) and Convergence Party backed the accord, with the Green Party the only one not to join in the pledge.
PRD representative Emilio Zebadua called the agreement "a framework we all agree on, one that assures that in 2006 Mexicans living abroad will be able to vote in the presidential elections."
Cecilia Romero, of the PAN, called the pact "a sign of the confidence that has been generated" after all candidates in the 2000 elections spoke in favor of enabling Mexicans living abroad to vote.
The PRI's representative said the parties have taken "a definitive leap" by signing the pact, which covers a gamut of issues ranging from legal and political to budgetary matters.
IFE figures show that 98 percent of Mexican expatriates live in the United States.
By 2006, an estimated 11.6 million Mexicans will be living north of the Rio Grande, including nearly 10 million of voting age a figure high enough to swing an election.