First, you will need a font that supports Korean. You could get it from your Windows\Fonts directory. I'll be using malgun.ttf as example here.

Copy the font to your device's Windows folder.

Using Registry Editor, navigate to the following key, [HKLM\Software\Microsoft\FontLink\SystemLink]

Append "\windows\malgun.tff,Malgun Gothic" (without the quotes) to all the values listed here. Below is the snippet of the modified values on my Omnia. Mine came with Chinese support original, explaining the extra fonts.

Courier New = \windows\sunfon.ac3,SC_Song;\windows\malgun.ttf,Malgun Gothic
Tahoma = \windows\sunfon.ac3,SC_Song;\windows\malgun.ttf,Malgun Gothic

You should be able to see korean now :D

P.S. Additional language could be added in this way similarly..

Tested and works for Omnia II =D

FontLink keys essentially extend a Western/Roman font to include non-Roman fonts. By enabling Font Linking as documented above, you enable WM6 to search for Korean characters. Inevitably, the operating system will find the correct Korean characters in Malgun.ttf and render them on your screen.