If you buy an iaito, you require a uniform and MUST join the All US Kendo Federation before you can practice with it.
Iaito length (and to a certain extent bokken) is dependent on your height…specifically the height of your hand above the ground. Please let me help you determine that length before you buy one. DO NOT buy garbage blades made of stainless steel, forged steel or Chinese swords. They’re EXTREMELY brittle and a safety hazard. They’re also not allowed at seminars or tests. And believe me, they check very carefully.
Your first purchase should be a good set of volleyball kneepads available at most sporting goods stores.
If you plan to keep on practicing, I recommend getting your own bokken (wood sword), saya (sheath), obi (belt…karate belts are fine for beginners) and sageo (cord to lash sword to belt).
If you plan on staying with the study of iai, you’ll eventually require hakama and gi. For beginners, hakama and gi (top) should match in color. Generally black for iaido and blue for jodo.
Obi (belt) color doesn’t matter. It doesn’t denote rank or standing.
Sageo color doesn’t matter either. I’ve seen some pretty wild ones on some students.
The All Japan Kendo Federation has a site available if you’d like a DVD of Seitei kata. The English version can be found at http://zenkenren-shop.com/en/eigo/index.html. It was also available free on YouTube at http://youtu.be/sDfcu9BP5fI
No idea if it’s still up. Please note that there are differences in this video from what is currently practiced. First, it’s a Shinden Ryu practitioner, so there are differences in style. Second, it’s almost 10 years old, so some techniques have changed subtly. If you see a difference from what I’ve told you to do, please talk to me before you change your technique.