Dzogchen Foundation
Biography, images, detailed Dzogchen lineage, teaching schedule, and selection of dharma teachings.
http://www.dzogchen.org/

RIGPA
International network of meditation centers and groups under the guidance of Sogyal Rinpoche, author of the Tibetan Book of Living and Dying, and H.E. Dzogchen Rinpoche.
http://www.rigpa.org/

The Dzogchen Community in America
The Dzogchen Community of Choegyal Namkhai Norbu in America. Audio teachings by Rinpoche. On-line bookstore.
http://www.tsegyalgar.org/

Namgyalgar
Choegyal Namkhai Norbu's Australian Dzogchen Community. It includes a description of Dzogchen and its relationship to Tibetan Buddhism, Norbu Rinpoche's biography, retreat schedules, and information on the Australian and Oceania Communities.
http://www.dzogchen.org.au/

Ligmincha Institute
Site for Dzogchen in the Bon tradition, the native religion of Tibet. Ligmincha was founded by Tenzin Wangyal Rinpoche, the first teacher of Bon Dzogchen in the West. Includes useful information on Bon Dzogchen, audio files of mantra chanting and an on-line store.
http://www.ligmincha.org/

mist-real
Mike Dickman's translations of several essential Dzogchen texts and commentaries. Mipham, Garab Dorje, and Dza Patrul Rinpoche.
http://www.jungcircle.com/mist/buddhism.htm

Dzogchen Lineage
The international community of Dzogchen Shri Singha International, practicing under the guidance of Dzogchen Khenpo Choga Rinpoche. Featuring background and historical resources on Buddhism and Dzogchen, current activities, and links to local organizations within the community.
http://www.dzogchenlineage.org/

Elias Capriles: Buddhism and Dzogchen
Two books and several papers by Capriles, on Dzogchen and Buddhism. Texts are available in zip format for downloading.
http://eliascapriles.dzogchen.ru/