ABC News, CBS News and NBC News will produce network special reports for the moment of silence to be held at 11amET for the victims of Saturday’s massacre in Arizona.  Diane Sawyer and George Stephanopoulos will anchor ABC’s coverage from Tucson. Erica Hill, also  in Tucson, will anchor for CBS and Matt Lauer will anchor for NBC with Brian Williams in Tucson. The cable networks will, of course, cover it as well. Pres. Obama will lead the moment of silence from the White House South Lawn.  The president has also signed a proclamation calling for flags to be flown at half-staff until sunset on Friday. Sawyer, Williams and CBS’ Katie Couric will all anchor their broadcasts from Tucson tonight.