http://www.guidetojapanese.org/learn/grammar
Tae Kim's *free* guide to learning Japanese grammar! He doesn't quite explain everything perfectly, so if you have any problems, just go to Tofugu, which is in the previous post. He also tries to get you using difficult kanji early on. I'm "cheating" and just recognizing where kanji goes and focusing on the grammar part so I can make sentences and put the kanji into them later. If you wanna learn more difficult Kanji early on, go right ahead. (^_-)~*