Can you tell us how you got the garbled text? It looks like if you switch the encoding, as suggested, that you might get things into something resembling Japanese.
As for Mac OS X supporting Japanese. I presume you have checked the system preferences. You can set it so it opens applications with Japanese localization, if available. While this might be useful to you at this moment, you can also add Japanese IME (input) to any application within the system preferences.
I use Mail from Apple without any issues. Occasionally someone's email is garbled (mojibake being the 'technical' term for this as it relates to Japanese) when some sets the text as single-byte...but this typically happens with MS clients such as Outlook (I use Japanese regional settings at work...and Outlook just botches things too much for my likes). Japanese characters are two-bytes each .... so parsing per one-byte just corrupts everything and makes 2x the characters out of the message. Anyway.
Using Perl's pack() and unpack() are good ways to keep things nicely packed into a format that supports two-bytes. Hopefully 5.8.0 will/does support Unicode fully. This is what I have done with Perl web-apps in the past.
But...it really depends on how you qualify "My next question is where there's a good online FAQ site for doing
japanese on OSX or finding OSX programs that accept Japenese (unicode?)."
Cheers, Ward
