Naval Leader Planning Guide 2014: from The Center for Personal and Professional Development, Naval Education and Training Command; available on Navy Knowledge Online (NKO)
Navy Leader Competency Model (NLCM): from The Center for Personal and Professional Development, Naval Education and Training Command
Lejeune Leadership Institute, Marine Corps University: the Lejeune Leadership Institute was founded 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.
Timeless Traits of Leadership: remarks by the Honorable John H. Dalton, SECNAV at USNA graduation, 31 May 1995
Principles of Naval Leadership: from the Naval Leader Planning Guide, 2003
Military Leadership: part of the Strategic Studies Institute of the United States Army War College; provides links to studies in a variety of military leadership categories, including Military Culture, Retention and Recruitment, Military Professionalism, Managing Change, and Managing Contractors.
Leadership, Ethics and Command Central, Air War College, Air University, U.S. Air Force: an extensive gateway to online resources relating to various aspects of leadership
Strategic Leadership Studies, Air War College, Air University, U.S. Air Force: provides links to many resources concerning great leaders, including biographical information and speeches, as well as other resources for teaching such as case studies.
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.