NON-PROFIT ORGANIZATION WEBSITES:

• American Society of Association Executives (ASAE)
• BBB Charity Reports--Better Business Bureau
• Board Source
• Council on Foundations
• The Foundation Center--"gateway to philanthropy;" search for tax filings for non-profit organizations
• Free Management Library
• GuideStar--Search for non-profit organizations.
• Idealist.org--20000 organizations in 140 countries.
• National Center for Charitable Statistics--Center on Nonprofits and Philanthropy at the Urban Institute
• National Council on Non-Profit Associations (NCNA)
• PEW Charitable Trusts
• Society for Non-Profit Organizations (SNPO)
• WINGS - Worldwide Initiative for Grantmaker Support / Corporate--Associations supporting corporate social responsibility.
• Nonprofit Organization Information from the Economic Research Institute

Also try the print source: The Foundation directory. Part 2. -- Q. 378.32 F822.