Dionne Warwick--recently named the unofficial U.S. "Ambassador of Health" by the Department of Health and Human Services--announced Wednesday she will organize an elaborate fund-raising weekend June 10-12 in Washington to raise money to fight AIDS. The money will be dispersed through the Warwick Foundation, which she recently formed to provide grants to health-related causes. Among those expected to participate are Gladys Knight, Stevie Wonder, Elton John, Whoopi Goldberg, Robin Williams, producer Aaron Spelling and composers Burt Bacharach and Carole Bayer Sager. Heavy hitters in Washington--including Speaker of the House Jim Wright (D-Tex.) and Sen. Edward Kennedy (D-Mass.)--are also on board. "More foundations must get involved in the AIDS fight and I challenge them today to join me in funding educational and health care services programs, as well as research programs," Warwick said in a speech before the National Press Club in Washington on Wednesday.