Foundation Support Organizations:

Council on Foundations
National association of grant makers offering training and support services.

Exponent Philanthropy (formerly Association of Small Foundations) 
National association of private foundations with few or no staff.

National Center for Family Philanthropy
National non-profit dedicated exclusively to families who give and those who work with them.

Philanthropy Roundtable
National association of grant makers that helps to foster excellence in philanthropy.

Philanthropy Southwest (formerly Conference of Southwest Foundations)
Regional association of grant makers covering Arizona, Arkansas, Colorado,
Nevada, New Mexico, Oklahoma and Texas offering training and support services.

Governance and Management Assistance:

CNM Connect (formerly Center for Nonprofit Management of Dallas)
Membership association of nonprofit organizations offering comprehensive management training and support services.

Independent Sector
National coalition of nonprofit organizations and grant makers.

Grant Research:

The Foundation Center
National clearinghouse of information about grant makers and their grants.

A central source of information on U.S. non-profit organizations.