This part of the site's probably going to remain heavy on the external links for a good while, at least, since I'm too lazy to mess with asian fonts, and I'm too persnickity to do pages on learning japanese with pure romaji.
Honorifics - really bad at the moment, not to mention purely yoinked from other sites
Glossary - gleaned from a couple books
Asaikawa - "Shallow River," a shamisen ditty
Basic (.doc file) - mostly grammar that I stole from some other websites (noted in the file) for my own use, but I did so much formatting that I didn't want to just throw it away ^^;;;.
Hip-Hop (.pdf file) - "aspects of Japanese Hip-Hop rhymes: what they reveal about the structure of Japanese"
Japanese (.pdf file) - for the Western Brain, by Kim Allen
Kendo (.doc file) - Japanese useful for Kendo [or wider applications, as well]
Nihongo o narau, the second-best language site I've found (and only lagging since it's only for one language). Very, very good introduction to japanese vocabulary and grammar and writing and such... ya get the point. Main source of my "Japanese Basic" file above. It even has practice kanji-writing paper o.O *squeal*.
Nihongo Shoho - 34 lessons, mp3 audio files, worksheets, kanji indexes... the works; I highly recommend this site
The Japanese Page - another pretty good site; the kanji section I especially like
Japanese through Castlevania - a gamer, motivated to learning the language for the sake of playing more games, apparently made this site. Not especially marvellous, but it's aight for a basic intro.
Japanese Vocabulary - this one was done by an otaku, and again, not an exceptional site, but it's got some good vocabulary and such.
More Vocabulary - yet another site that's good for little other than having some amusing vocabulary
Vocabulary Testing Program - downloadable here; it sounds like a great program, but since I have a mac and it's .exe [so I can't run it], I'm unable to vouch for how good it actually is
Mononoke Hime - annotated script with japanese text; since the best way to learn is to plunge in headfirst, wot?
Japanese Lessons: Classroom - decent site, although it hasn't been updated since mid-2000... the main thing I liked about it was that it had sound files (!!).
The Kanji Site - somewhat confusing, but contains a lot of useful information on various kanji once you figure it out
Tim's Takamatsu - some "drillers" and nice explainations of various issues of the language
Griffth University - their "Japanese Resource Home"; contains "resources" on Kanji and Grammar.
JBall - basic Japanese kanji; they have ten lessons [very basic].
Head Expressions - about.com's section on ... well, expressions that use "atama," or head.
Japanese Language - Japan Guide's [which is itself a very good site to navigate around on, even if their language page isn't extremely useful] page on the language
jeKai - a Japanese-English dictionary project
Japanese Grammar - a slew of pages on the stuff. Quite good.