Human Costs in Iraq Act of 2008 - Amends the Department of Defense Appropriations Act, 2008 to require, in a report concerning Department of Defense (DOD) progress toward military and political stability in Iraq, additional information concerning: (1) the total number of Iraqis killed by violence; (2) best efforts to distinguish between combatants, noncombatants, and official Iraqi Security Force personnel killed; and (3) details of the incidents involving each casualty.