Japanese: The Hardest Language in the World

http://www.languagerealm.com/japanese/hardestlanguage_jp.php

Tim's Takamatsu Verb Lessons

This site is great. It covers both a lot of verb rules in a clear manner and a lot of vocabulary along with it. Good for beginners and for more advanced students: http://www.timwerx.net/language/jpverbs/index.htm