Joel Klein, former Clinton administration antitrust chief, last week was named chairman and CEO of German media giant Bertelsmann's U.S. operations in New York. Klein, 54, is best known for suing Microsoft Corp. on antitrust charges. He previously was a deputy counsel in the Clinton White House and a private attorney. Bertelsmann has stakes in several U.S. media enterprises, including 41% of Barnesandnoble.com. The company also has an agreement to launch a subscription-based Internet music service with de Napster.