Zen -- Excerpt from The Tao of Physics
"Zen is a unique blend of the philosophies and idiosyncrasies of three different cultures. It is a way of life which is typically Japanese, and yet it reflects the mysticism of India, the Taoists' love of naturalness and spontaneity and the thorough pragmatism of the Confucian mind."
http://www.shotokai.cl/otras_artes/165_em_.html

Zen Guide
An attractively presented online introduction to Zen. Resource intensive; may crash your browser.
http://www.zenguide.com

Lecture On Zen
by Alan Watts
http://deoxy.org/w_lectur.htm

The Kyosaku Explained
The Kyosaku is a blow on the shoulder with the light stick carried by a Zen priest during meditation.
http://www.pvtnetworks.net/~kmcguire/kyosaku.html

Zen Frequently Asked Questions
An introduction to Zen
http://www.zenproject.faithweb.com/zen_teachings/what_is_zen_buddhism.html#what_is_zen_historical

180 Questions and Answers about Zen from Master Deshimaru
On questions regarding the middle way, ego, karma, illusions, attachement, helping others, good and evil, death, modern civilization, everyday life, Christianity, consciousness, impermanence, here and now, satori, practice, zazen, posture, and tradition.
http://www.zen-deshimaru.com/EN/sangha/deshimaru/QR.htm

Wikipedia: Seon
Extensively cross-indexed article on the Korean form of Zen.
http://en.wikipedia.org/wiki/Seon

Frequently Asked Questions from alt.zen
http://www.ibiblio.org/zen/faq.html