CHIN @MUSUBANA, as you own a Mac, you do not need a CJK input device. Your keyboard will do as well. Simply activate the ITABC Input Method in the System Settings, Localisation or Country Settings (I do not know exactly the wording as I am using german localisation). If you enable to show the keyboad menu within the menu bar, you may select the chinese flag and then you can simply input the romanized form that program produce (but without the accents) and you get a selection of all those chinese characters that will match the sound you wrote. Select the one you mean and you are set. :-)
For instance: typing hanyu will produce 汉语 following that method.
Is the Mac not a nice toy? :-)
(Version 2.1)