The nation's capital began preparations yesterday for a historic weekend, when civil rights matriarch Rosa Parks will become one of only 30 Americans ever honored with the pomp and ritual of a Capitol Rotunda viewing.

The woman who quietly refused to give up her bus seat to a white man in Montgomery, Ala., a half-century ago will be the first woman and the second African American to lie at the same exalted place as presidents and war heroes.

The tribute became official yesterday when the House passed a resolution approved earlier by the Senate, honoring a woman whose courage helped spark the civil rights movement and, eventually, landmark federal legislation.

So, yesterday, the machinery of protocol began its decades-old ritual of remembrance. The Rotunda will be open for public viewing of Parks's coffin from 6:30 p.m. to midnight tomorrow and from 7 a.m. to 10 a.m. Monday.

Many expect the vigil to draw crowds of people who remember Parks as a role model and an icon of the civil rights movements.

"I can't imagine a higher honor than this," said Richard Baker, chief Senate historian, who has studied and documented events beneath the great dome for three decades.

Parks transcended the partisanship that has deadlocked Congress on other issues. Within days of her death, Rep. John Conyers Jr. (D-Mich.), who employed Parks for 20 years in his Detroit office, had moved the resolution through both houses of Congress, with support from both sides of the aisle.

Baker said of Parks: "It's been a long road from that bus seat to the Capitol Rotunda in Washington. This is a great memorial to the courage of one person."

Buses will become part of the symbolism of the moment. Sixty Parks family members and dignitaries traveling from Montgomery will board three Metro buses draped in black bunting. The procession will be led to the Capitol by a 1957 bus, which will be empty of passengers, said Candace Smith, a Metro spokeswoman.

After memorials in Montgomery tomorrow, the coffin will be flown to the Washington area on a plane provided by Southwest Airlines and commanded by one of the first African American chief pilots for a commercial airline, said John C. White, spokesman for the NAACP.

The entourage and hearse are scheduled to arrive at the Capitol from Baltimore-Washington International Thurgood Marshall Airport at 5:30 p.m. The coffin will enter the Capitol via the grand East Steps. There will be a tribute including a choir, wreath laying, and prayers, followed by the public viewing.

Mourners will line up at the West Entrance to be processed through the visitor screening center. There will be 12 metal detectors to search for weapons and other prohibited items, including recording devices. Police will not allow chairs, umbrellas, coolers, sleeping bags, large backpacks or other bulky items. Officials will not allow photography in the Rotunda; they have not yet decided whether to ban cameras. Prohibited items can be checked at the entrance and reclaimed after the viewing, said U.S. Capitol Police Chief Terrance W. Gainer, who will follow the same crowd-control plan used during President Ronald Reagan's viewing last year.

After the viewing Monday, the coffin will be taken to Metropolitan AME Church in downtown Washington for a 1 p.m. memorial service. D.C. police said they will restrict parking and traffic in the area of 15th and M streets NW all day for the service. Afterward, the coffin will be taken to BWI and flown to Detroit, where there will be another vigil and then burial Tuesday.

In the past, the nation has come to the Capitol to pay tribute to presidents, senators, generals and unknown soldiers. This is the first time a private citizen renowned for social activism and the first time a woman will be the focus of the ritual.

Mary Francis Berry, a former chairman of the U.S. Commission on Civil Rights, said scores of people will pay tribute because Parks was a champion of ordinary people. "Here is a person who is in relative obscurity, who made an enormous change," Berry said. "Sometimes the most unlikely people can make a difference if they are committed to a principle."

Parks is again making history, admirers said. "There has to be a standard for a civilian to be accorded such a high honor," said Del. Eleanor Holmes Norton (D-D.C.) "Rosa Parks has met that standard of extraordinary service to her country. She didn't have a weapon on her. She didn't have an organization behind her. All she had was her conviction."

The tribute, which requires an act of Congress, has taken place 30 times, historians say. The first person so honored was Henry Clay, in 1852. The last person was Reagan, in June of last year. Others were nine presidents, eight members of Congress, an admiral, two generals, two government officials, two Capitol police officers slain at their posts, unknown soldiers and Pierre Charles L'Enfant, the architect who designed Washington, D.C.

"I think it's a very powerful message honoring Ms. Parks and, therefore, so many who did so much for the cause of equality," said Mark Pelavin, associate director of the Religious Action Center of Reform Judaism. "More than that, highlighting Ms. Parks is an opportunity to highlight the tremendous impact that one individual can have, even in moving a nation."

The Rev. Grainger Browning Jr., pastor of Ebenezer AME Church in Fort Washington, said he expects many from his flock to attend the tribute at the Capitol because members of the Parks family were longtime members of the church.

Fred Gray, the Alabama lawyer who represented Parks after she was arrested, said many leaders of the civil rights movement will be scrambling to get to Washington this weekend.

Staff writer Robert E. Pierre contributed to this report.

Alexandria Lockett, left, and Tyra Robinson sing "Oh Freedom" during a memorial service to honor Rosa Parks in Montgomery, Ala.

Montgomery Mayor Bobby Bright, left, the Rev. Joseph Rembert, former Atlanta mayor Andrew Young and the Rev. Michael Thurman sing "We Shall Overcome" as service ends at Dexter Avenue King Memorial Baptist Church.