This episode's headline: Olympic Investigation Year of Disasters; Slowing Down; Conversation. ANCHOR: JIM LEHRER; GUESTS: CHRISTINE BRENNAN, Sports Writer; HOWARD BERKES, National Public Radio; JANET ABRAMOVITZ, Worldwatch Institute; JOHN CLIZBE, American Red Cross; BOB WATSON, World Bank; HENRY KAMM, Author;CORRESPONDENTS: TOM BEARDEN; ROD MINOTT; PHIL PONCE; TERENCE SMITH