WASHINGTON (AP) - Federal Emergency Management Agency director Mike Brown resigned Monday, three days after losing his onsite command of the Hurricane Katrina relief effort. The White House picked a top FEMA official with three decades of firefighting experience as his replacement. R. David Paulison, head of FEMA's emergency preparedness force, will lead the beleaguered agency, according to two senior administration sources who spoke on condition of anonymity because the announcement had not yet been made. Paulison is a career firefighter from Miami who was among emergency workers responding to Hurricane Andrew in 1992 and the crash of ValuJet Flight...