Useful sites for learning Japanese grammar.
http://www.maggiesensei.com/
http://www.guidetojapanese.org/learn/grammar
http://www.yomiuri.co.jp/dy/columns/0002/ Pera Pera Penguin

Resources:
http://jisho.org/
http://www.japaneseverbconjugator.com/JVerbList.asp
http://www.jgram.org/pages/viewList.php?t=15
http://www.kansaiben.com/