Multilingual site And PHP

It's no surprise iso-8859-1 doesn't work, since that character set doesn't include Chinese, Korean, or Japanese characters.

UTF-8, however, does. When you switch to UTF-8 are you both converting your output to UTF-8 and setting the Content-Type header? You should be doing this at the beginning of your script:

header('Content-Type: text/html; charset=utf-8');

mb_http_output("UTF-8");
ob_start('mb_output_handle

r');
?>