If you are using Window XP/ Vista/ 7 You don't need a program for it. Go to Start > Contro panel > date, time, language and regional options > Languages > check 'Install files for east asian languages > Go to Advanced(which is next to 'Languages') > check '10003(mac-korean)' > click "select a language to match the language version of non-unicode programs you want to use" > select Korea and click Ok. And then check your taskbar on the bottom of your monitor. If you click on it or simply 'Alt" you could see FR or ENG changes to KOR This is how you can try on XP, not sure if it would be exactely same on Vista or 7 but guess it won't be so different. Hope it helps.

I'm using NJStar Communicator. It's can type in Korean, Chinese, or Japanese. Or you can Install from regional settings if you are using Microsoft Windows