Management and Supervisory Development

American Management Association

Access requires free signup.  Site features interactive "Thinkers Series" and an extensive library of articles and e-books

Association of Executive and Administrative Professionals

Salary survey sample available for free. Membership benefits include access to job postings and career sponsorship

Business and Professional Women/ USA

Political advocacy group for workplace rights for women.  Newsletter and calendar, links to local chapters

International Association of Administrative Professionals

Publisher of Office Pro magazine.  Site provides links to training for certification and virtual learning for members

Management, Leadership, Business Strategy, Small Business

Selective and informative directory in the About.com Human Resources section

DVDs for Managing and Supervising:

emotional intelligence

employees

interviewing

stress management