I've had a lot of difficulty with that.
Are you looking for actual Japanese character fonts?
Almost all the ones you'll find on the web are Kanji-ised (not a real word) versions of our Latin alphabet that are pretty stereotypical and cheesy.
Most of them quite Chinese looking too.
I've searched long and hard to find a solution but there seems to be quite a culture gap here and not only is there the issue of getting a Japanese font but it's also the issue of using a Western keyboard as well.
There are some Japanese fonts on the Mac system fonts but you need to paste the Japanese in that you've found somewhere else unless you can write Japanese of course.
Google translate is pretty good for this but you have to be careful.
I often make my own versions from that.
Maniackers has some really cool fonts and it's worth a visit just to look at the A-Z example pages which are awesome by themselves and great inspiration.