The Internet home for the Association of Professional Researchers for Advancement.
UVA's research link collection.
A comprehensive list of research links from the University of Southern California. Notable for its section on international company sites.
RI Arlington is a systems consulting firm that serves non-profit organizations and development offices with a variety of services. Their home page is an encyclopedia of advancement services. In addition to the research links, there's an advancement services salary survey and a job board.
A resource aimed at journalists, but with obvious applications for prospect researchers.
This site, run my friend Gregg Meister, has a number of useful resources for churches and religious organizations. His company, Interlink Media, provides a full range of multi-media services geared especially for non-profit organizations.
My family has been involved with several trips to the Dominican Republic sponsored by the Foundation for Peace. These are not tourist trips, though I think we saw the DR like no tourist ever does. The foundation works hand-in-hand with people in need in developing countries to enable their emergence from poverty.
Research Consulting Firms
(In no particular order)