Update for Ubuntu 14.04.01
After installing Ubuntu, go to language support. Choose Korean to add language.Then, restart the system and go to “text entry” and choose “korean (hangul)”, not just “korean”.
If you choose just korean from text entry, you can’t see korean characters even though the input language already has been changed to korean.
Please have a look the following link.
After Korean language pack installation, one might need to set up input method in the Language support window.
Log out also is required.
The above page is deprecated and no longer valid.
Updated version is
Install Korean keyboard layout by going to System Settings> Keyboard Layout. Click on “+” sign at the left bottom corner, select Korean from the list and close. Click on Options button and select Keys to change layout, then select from drop-down list of checkboxes Left Alt + Left Shift and close the window.
Enable Korean language support by going to System Settings> Language Support. Click on Install / Remove Languages, select Korean from the list and Apply Changes. Select ibus as the Keyboard input method system.
Type ibus in the dash and run Keyboard Input Methods application. The IBus preferences window will be opened. Select ‘Input Method’ tab, then ‘Select an input method’ combobox and Korean from dropdown menu.
To switch between Korean Hangul mode and English ‘Roman’ mode: use Ctrl – Space keys combination (set by default).
You need to reboot the Ubuntu.