The U.S. Marshals Service is part of the Department of Justice, headed by a director appointed by the president. As of May 2007, former marshal John F. Clark was the director. The service is headquartered in Arlington, Virginia.
Marshals work in one of 94 districts throughout the country - each district coincides with a federal judicial district, so that each federal court has its own marshal. The U.S. Marshal for a given district is in charge of that district. The other officers that work in the district are deputy marshals and criminal investigators.
The U.S. Marshals Service shouldn’t be confused with other kinds of marshals. Marshal is a common title with a variety of uses. Some nations use it as a military rank. State and local courthouses have their own marshals, a title that basically means 'judicial security guard.' Air Marshals are specially trained officers who travel on certain airline flights, remaining undercover unless they are needed to quell a disturbance of some kind on the plane.
Formerly, applicants were required to take a special exam. Today, the Marshals Service uses the Federal Career Intern Program to find new hires. This is a two-year training and development program that can culminate in official hiring into the service if the candidate’s performance was adequate. Prospective marshals must complete 17 and a half weeks of training at the U.S. Marshals Service Training Academy in Glynco, Georgia. Anyone interested in becoming a U.S. Marshal can find contact information for their local recruiter here: USMarshals.gov.