Found a great little tool for inserting furigana into Japanese pages, making them easier to read for those who don't know all the kanji but have knowledge of katakana and hirigana.
As an additional tip, you can do this by prepending “trans.hiragana.jp/ruby/” onto the URL of the website you wish to insert the furigana.
*NEW* I've added a bar at the top of the site that allows you to put in the URL there as well. Enjoy!
Overall, it's pretty accurate, but you can occasionally get an inaccurate reading, so be careful.