MSNBC, CNN, and AP are all reporting that President Obama has relieved Gen. Stanley McChrystal of command. President Obama will make a statement at 1:30PM Eastern Time on the matter. Update: The NBC News report.
Update 2: AP is reporting that Gen. David Petraeus will be named McChrystal's successor.
Update 3: Live video feed from NBC, including President Obama's statements, expected any minute:
Update 4: New York Times coverage.