Yoroiden Temple
Here is a great resource for Samurai Troopers information.  (ST being the Japanese version of the show, which differs a bit from the American one.)

The Call
A good site for basic information and a GREAT links section.  With that links section one hardly needs to list any more.

The Ultimate Ronin Warriors Website
Here is Dawn Sanada's site, full of information.

Shin's Kitchen
Here is another informative website.

Animelab
This is a great Japanese-English dictionary, among other things.  (You may need to download the plugin that lets you see Japanese characters.  It is also down on occassion.)

Kiki's Kanji Dictionary
And here's a very cool kanji site.

Japan on About.com
This site has links to sites for Japan's language, their customs, and all sorts of useful things.

Japanese Schools
Another very useful link if basing your story in Japan.

Japanese Sword Glossary
This is a very informative site on the various styles of Japanese blades.

Samurai
Some information on the Samurai.

Japanese Armor
This site sells replicas of Japanese armor, and also has some interesting information about it.

Kendo World
Here is a website for a Kendo magazine, kendo being, of course, the art of Japanese swordwork.

.