Regional Corporations

13th Region
Ahtna Incorporated
Aleut Corporation
Arctic Slope Regional Corporation
Bering Straits Native Corporation
Bristol Bay Native Corporation
Calista Corporation
Chugach Alaska Corporation
Cook Inlet Region, Inc.
Doyon, Limited
Koniag Incorporated
NANA Regional Corporation, Inc.
Sealaska Corporation

Urban/Village Corporations

Afognak Native Corporation.
Barrow - Ukpeagvik Iñupiat Corporation. No website found, but the companies they run have sites - here is one.
Bethel Native Corporation
Chenega Corporation, a village corporation in the Prince William Sound area.
Eyak Village Corporation
Goldbelt, Inc.
Haida Corporation
Klukwan, Inc.
Kuskokwim Corporation (a merged village corporation for 10 middle Kuskokwim villages, The villages include Lower Kalskag, Upper Kalskag, Aniak, Chuathbaluk, Napaimute, Crooked Creek, Red Devil, Georgetown, Sleetmute and Stony River. )
Shee Atika, Incorporated

A few more links that might be helpful:

Administration for Native Americans
Alaska Federation of Natives
Alaska Growth Capital
Alaska Village Initiatives
Alaska Native Heritage Center
Alaska Native Knowledge Network
Alaska Native Studies Curriculum and Teacher Development Site
Alaska Native Subsistence Lifeways and Oral Traditions
Bureau of Indian Affairs
Institute of American Indian & Alaska Native Culture & Arts Development
Native American Indian Resources
University of Alaska Justice Center Web Site - Alaska Natives and First Nations Festival of Native Arts