The Smithsonian Institution's party planners yesterday issued the final word on their New Year's weekend headliners: The king will be coming, the queen won't.

Legendary bluesman B.B. King will appear the afternoon of Jan. 2 as part of the Smithsonian's "America's Millennium on the Mall" festivities, although not in an outdoor concert as organizers announced prematurely in September. Instead, King will play and talk about the evolution of his music in the far more intimate setting of the National Museum of Natural History's 565-seat Baird Auditorium.

Intimacy has its drawbacks, however. Tickets for New Year's weekend programs became available only on Monday, and those for King already are gone--although Smithsonian officials were not allowed even to utter the initials B.B. publicly until today because of contractual obligations related to the musician's concert last night at Constitution Hall.

The Smithsonian had hoped for a similar millennial "conversation" with the queen of soul, Aretha Franklin, who agreed months ago to perform Jan. 2 on the Mall. But when budget constraints forced organizers to move the program to three museum auditoriums, Franklin's promoters nixed her participation. The changed venue also led to the cancellation of rock-and-roller Chuck Berry's Jan. 1 show.

"We're disappointed, of course," said Richard Kurin, director of the Smithsonian Institution's Center for Folklife Programs and Cultural Studies and the man in charge of the weekend's exhibits, readings and lectures. "Because we've changed the nature of the event . . . we feel we cannot do inside a museum what they'd like to do."

Although Franklin and Berry were among the biggest names in the initial lineup, Kurin is taking their loss in stride. More than 50 people--from actor Edward James Olmos and civil rights activist and scholar Julian Bond to scientists at the Search for Extraterrestrial Intelligence Institute--are part of the eclectic discussions and performances the Smithsonian will offer Dec. 31-Jan. 2.

About 12,000 people will be able to attend the nearly three dozen events in the auditoriums at the National Museum of Natural History, the National Museum of American History and the Hirshhorn Museum. About 5,000 tickets--which are free but required for admission--already have been requested through the Smithsonian's number (202-786-9115 or 202-633-9467 TTY).

"My only sorrow is we don't have places to accommodate larger audiences," Kurin said. Already, tickets also are gone for the Dec. 31 discussion with Neil Gershenfeld of the Massachusetts Institute of Technology on future technologies.

One small consolation is that all sessions will be taped for dissemination through cyberspace Webcasts. The schedule, including plans for the outdoor gala that will begin at 10 p.m. New Year's Eve at the Lincoln Memorial, is on the Internet at www.americasmillennium.gov.

The Smithsonian's program schedule and ticket information also are listed today in the Weekend section of The Post.

Details for the District's "Main Street Millennium" on Dec. 31 and Jan. 1 are still being fine-tuned, though city officials said yesterday that a complete schedule soon will be posted on the Internet at www.2000dc.com. The centerpiece of the free D.C. festival, which will stretch four blocks of Constitution Avenue NW, will be the "Millennium Washington Stage" at 12th Street. Music will begin at 11:30 a.m. on New Year's Eve with the Latin band Ivan Cuesta y sus Vallenatos Autenticos, and Big Joe & the Joe Stanley Quartet will swing from 10 p.m. to nearly midnight.

Organizers said yesterday that about two dozen food vendors will offer Jamaican, Indian, Asian and other cuisines in heated pavilions that will spotlight each of the city's quadrants. The city is charging each vendor a $1,000 upfront fee and will receive 15 percent of sales.