Major International Karate Sanctioning Bodies

WKF (World Karate Federation - formerly known as WUKO)
http://www.wkf.net/

ITKF (International Traditional Karate Federation)
http://www.itkf.org/

IKO (International Kyokushinkai Organization)
http://www.kyokushinkaikan.org/en/index.html

JKA (Japan Karate Association)
http://www.jka.or.jp/english/e_index.html

Other Links

NASKA (North America Sports Karate Association)
http://www.naska.com/

PKA (Professional Karate Association)
http://www.pkakickboxing.tv/index.html