I currently live in china and deal with this all of the time. Usually the problem is not the font the way the characters are represented. All unix variants use UTF-8 (most os's) Windows uses UTF-16/32 (I forget). The cool thing about UTF-8 is that it is backwards compatible with ASCII. Open your text in the text edit or firefox. In firefox you can tell the browser to try different encodings, then save it to a file. If it is the wrong in coding Mac TextEdit can convert between UTF-8 and UTF-16. Once you have the string in UTF-8 encoding you can display it in your text field.
When displaying text to a textfeild make sure an display a utf8 string not an ascii string.
If you are interested in the details of utf8, just say so and I will expand on the utf8 design.
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