• President Obama has ordered the flag of the United States to be flown at half-staff at the White House and upon all public buildings and grounds, at all military posts and naval stations, and on all naval vessels of the Federal Government in the District of Columbia and throughout the United States and its Territories and possessions on 09-12-2012 until sunset 09-16-2012. You can view President Obama's proclamation here.
• Fly the US flag at half-staff on September 12th, 2012 until sunset September 16th, 2012. For U.S. flags displayed on a short staff or for indoor flags that cannot be lowered to half-staff, place a Black Mourning Ribbon Above the full staffed U.S. flag
• The correct procedure for displaying the flag at half-staff is to raise the flag to the top of the pole briskly, pause for a moment, and then slowly bring it down to where the top of the flag is at a position approximately halfway between the top and bottom of the pole. At the end of the day, the flag should be raised briskly to the top of the pole, then lowered slowly and ceremoniously retired for the day (unless illuminated at night).