[SamuraiAlchemistNinja]

There is a book I've read several times over that I believe is very helpful. "Making Sense of Japanese: What the Textbooks Don't Tell You" (Rubin) which I actually ordered on Amazon.com. It isn't boring, a little humorous at times, actually, and it's very informative and helps to clear up a lot of confusion on different difficult areas of Japanese, such as wa and ga and passive/causitive forms.