Foundation Center - One of the leading source of information about philanthropy worldwide. The Center maintains the most comprehensive database on U.S. and, increasingly, global grantmakers and their grants.
Guidestar - An organization that gathers and publicizes information about nonprofit organizations. They are a great resource to look up information on nonprofits. They encourage nonprofits to share information about their organizations openly and completely. Any nonprofit in their database can update its report with information about its mission, programs, leaders, goals, accomplishments, and needs --for free.
Washington Regional Association of Grant Makers - a membership organization of independent foundations, community foundations, operating foundations, charitable trusts, corporate foundations and corporate giving programs that promotes and supports effective, strategic, and efficient charitable investment in the Greater Washington region.