DiRhody's Resources - Celebrating the True Worth of Highly Gifted Children and Adults. Contains information about  standardized test known as the Stanford-Binet Form L-M. 

The Outsiders - An EXCELLENT must-read article by the late Grady Towers on the gifted condition and things that the Terman Study overlooked. 

High IQ Societies - Information on the existing high IQ societies and their acceptance criteria. 

Hollingworth Center for the Highly Gifted - A National Volunteer Resource and Support Network for Highly Gifted Children, their Families, Schools and Communities.

Summer Institute for the Gifted - University Resources for the Gifted and Talented. The Universities listed participate in year round research to enhance the education of the gifted and talented. They offer gifted and talented students the opportunity to participate in programs and courses in the spring, summer and fall.

GTWorld - GT World is an on-line support community for gifted and talented individuals and those who support and nurture them (highly recommended by Enigmadness.com). They offer several lists depending on your special needs.