This episode's headline: Toppling Saddam; Gergen & Shields; Homeless No More; Rebuilding Hesston. The guests include DAVID GERGEN, U.S. News & World Report; MARK SHIELDS, Washington Post; MOHAMMED SAID DOSKY, Iraqi Opposition; SAMIR AL- KHALIL, Middle East Analyst; SEN. JOHN WARNER, [R] Virginia; NICHOLAS VELIOTES, Former State Department Official; A.M. ROSENTHAL, New York Times; CORRESPONDENTS: LEE HOCHBERG; JIM FISHER. Byline: In New York: ROBERT MacNeil; In Washington: JAMES LEHRER