A campaign official confirms that Tom Hanks is indeed the narrator of the documentary, which is directed by Academy Award winner Davis Guggenheim.
UPDATE: The Republican National Committee responds:
“The American people don't need a movie trailer or a 17 minute documentary to know what the president accomplished over the past three years. Unfortunately Americans feel Obama’s accomplishments each and every day after President Obama led our country to higher unemployment, record debt, and higher gas prices. The question is what does another Obama term mean for America? From the promise of fewer jobs, tax increases, more debt, and the implementation of Obamacare, we literally cannot afford another four years of President Obama.” – RNC spokesperson Kirsten Kukowski