International Society for Military Ethics (ISME): Formerly the Joint Services Conference on Professional Ethics (JSCOPE); "an organization of military professionals, academics and others formed to discuss ethical issues relevant to the military; provides case studies as well as links to other ethics web sites and sites for the core values of the U.S. Air Force, U.S. Army, and U.S. Navy.
The Lejeune Leadership Institute: "Organized to advance the study and practice of leadership excellence focusing on leadership development that is founded on marine Corps values;" branches of the Institute cover Support, Doctrine, Ethics, Professional Programs, and Civilian Leaders Development Program.
U.S. Department of Defense Standards of Conduct Office (SOCO): Provides news and resources to assist all DoD employees, civilian and military, to understand the ethical standards that apply to all DoD employees; includes SOCO publications and handouts and links to statutes, regulations, executive orders, directives and instructions; an Encyclopedia of Ethical Failure provides case studies of real situations and their disciplinary resolutions.
VADM James B. Stockdale Center for Ethical Leadership, U.S. Naval Academy: The mission is "to empower leaders to make courageous ethical decisions; includes an electronic edition of Ethical Leadership for the Junior Officer and Ethical Leadership for the Junior Staff Corps Officer (sponsored by the USNA class of 1964) as well as articles, speeches and videos.
The Internet provides access to a wide variety of information - some good and some less reliable. Use care in deciding which sites to use for research. These are some tips for assessing the quality of a web site. Ultimately, you need to look for currency, relevance, authority, accuracy, and purpose.