Morning Buzz: March 1, 2007

This morning's top stories:

• In its ongoing investigation of poor conditions at the Walter Reed Army Medical Center, the Washington Post reports today that top medical officials had been aware of complaints of substance abuse and other problems at the facility for several years.
• North Korea's second highest-ranking official has pledged his commitment to giving up the nation's nuclear program, the AP reports.
• Plans are moving ahead for a March 10 summit on Iraq among key Middle East and western countries, but it remains uncertain what role Iran will play in those talks.
• U.S. News reporter Alex Kingsbury sends us two items from Baghdad: what you can tell about the capital from what people are buying, and more details from the video we showed you yesterday on a visit to a new Iraqi school.