Kyudo.com
The name says it all. It's a rich resource, the most important part of which is the links to "U.S. organizations, instructors and events operating under the auspices of the International Kyudo Federation (IKYF) and the All Nippon Kyudo Federation (ANKF)"

Oko Kyudokai
The European Kyudo organisation of Zenko International founded by Kyudo Master Kanjuro Shibata XX.

London Kyudo Society
"The London Kyudo Society is a private voluntary body established to promote the practice of Kyudo - the traditional art of the Japanese bow. It is open to all who have an interest in Japanese traditional culture and in a practical way wish to take on the challenge and demands that Kyudo has to offer."

Kyudo Renmei Netherlands
The official website of the Kyudo Renmei Nederland (both in English and Dutch)

All Nippon Kyudo Federation
The official ANKF site (in Japanese)

Takeda School Kyubadou Yabusame
A kyubadou ("the way of the mounted archery") Japanese site (the great one, IMHO) (both in English and Japanese)

FFKT - Fédération de Kyudo Traditionnel
French Federation of Kyudo. It has the links to French kyudo organizations and dojo, as well as general information on kyudo (in French)

Kiel's Kyudojo
A German kyudo webside (in German)

Kyudo Club Torino
An Italian kyudo club (in Italian)

Kyudo web site
A Polish kyudo website (in Polish)

弓道活劇 with Flash
A fun site with flash-movies dedicated to kyudo practice (in Japanese)

"My experience of Kyudo in Japan"
A personal webpage of Bob Ridge with the sharing of his kyudo experience in Japan.

The Kyudo Project Incorporated
As site it says, "A California 501.3 (c) non-profit corporation dedicated to spreading timely and accurate information about Kyudo". It has a lot of links and articles, mostly useful, but some doubtful (although, it's for you to judge), but worth visiting.

...more links to be added...
don't hesitate to suggest other resources in the comments to this post