For the second time in as many days, President Obama is speaking before the United Nations' annual gathering of world leaders. Yesterday, he focused on development issues at the Millennium Summit. Today, he speaks to the General Assembly. To analyze the president's address and report on reaction at the U.N., we turn to Colum Lynch, U.N. correspondent for The Washington Post.

In 2007, after working for four years to organize a sting operation, U.S. agents apprehended an Iranian arms smuggler. The Philadelphia Inquirer's John Shiffman details the operation that snagged Amir Hossein Ardebeli, who bought largely from American companies.

The White House made it official this week — top Obama economic adviser Larry Summers will return to his post at Harvard. He is the third senior economic adviser to quit the administration this year. We speak with Peter Morici, business professor at the University of Maryland, about the candidates to replace Summers, and what the choice will say about the Obama administration's economic policy.

Nations bordering the North Pole are holding a summit to discuss how to share the area's potential riches, like the gas and oil that are becoming more accessible due to global climate change. The BBC's Rajesh Mirchandi reports.

Do you mix-up, mispronounce or mangle words? The editors of the American Heritage dictionaries can help. They've put out guides like "100 Words Almost Everyone Mixes Up Or Mangles," "100 Words Almost Everyone Mispronounces" and "100 Words Almost Everyone Confuses And Misuses." We talk words and word usage with one of those editors, Steve Kleinedler of the American Heritage dictionaries.