(It's true. I'm getting ready to make costumes, but the truth is, I had these links saved already cause they help me describe and understand stuff better)
This one tells you the name and how to wear most of the armour a better dressed Japanese soldier would wear (although most of the foots soldiers weren't dressed this well), and even tells you how to make a lot of them:
Some stuff about portraying Buddhist monks which has info which can be used by writers:
A neat site on Kosodes including information about how they were decorated and how to make'em.
Patterns for women's hakama
(including how to tie them. they are tied differently than men's.)
A pattern for men's hakama (period correct, not like modern sport hakama)
And there's always the wonderful Costume Museum: