This is embarrassing to admit, but I still struggle to use Japanese characters on my computer. Despite installing Microsoft's East Asian Language support over a year ago, I still occasionally have problems toggling between roman characters and kana.

Needless to say, I was happy to discover Typd.in, a website that makes it easy to type the characters from the web. 例えば、私はそれがこの文章を書いていた (for example, I used the service to write this sentence). In addition to the web interface, there's also a JavaScript Bookmarklet that you can use to convert text fields on other web pages into kana input fields.

すばらしい!