Tae Kim, the author of the useful Japanese guide to Japanese grammar offers up this site. What you will find here are tidbits about Japanese that he hopes will be useful for those studying the language. He plans to separate posts into three major categories: Beginner, Intermediate, and Advanced. The beginner category will talk about the fundamental principles of Japanese such as particles, parts of speech, and simple expressions. The advanced category will cover things like formal language and various written expressions. Everything in between will go in the intermediate category.