I don't have a mac, but I ran into a problem when
trying to view Japanese web pages as well. While
checking out options, I found a page that sounds
like it could help mac users. Here's a URL of the
page (also above):
http://kentaro.com/#i-like-japan

Scroll to the bottom of the page to get a 
description of the program and a link to what
looks like a free download. It's called "I like
Japan". (Catchy, eh?) I hope this helps! If not,
then blame my macintosh illiteracy. 

-sawyer