EDIT: untested with Zune Software firmware v2

This hack / mod will allow you to install support for Asian Languages - Korean, Japanese and Chinese - on your Zune. It was also done some days ago but it required to open your Zune and use an adapter to access it's hard-drive. Below is the Software-only solution...

Scheme, who also found the way to do the hardware hack, posted this Software-Only solution too (Korean only). You can use Babelfish to automatically translate it to English. Here is also the Hardware Solution .

What you will need to download:
Java Runtime Environment - JRE (If you don't have it already)
Zune.RE.zip
Microsoft Cabinet Software Development Kit
Zune Firmware v.1.2

ZuneBoards has posted a human translated English howto: 

Make sure these fonts exist in your computer. If not, you must download the East Asia Language Pack from Microsoft:

%systemroot%\fonts\gulim.ttc
%systemroot%\fonts\mingliu.ttc
%systemroot%\fonts\msgothic.ttc
%systemroot%\fonts\simsun.ttc

1. Run the Microsoft Cabinet Software Development Kit (cabsdk.exe) you have downloaded. When asked to unzip/extract, create a folder and extract the files into that folder.

2. Then, copy firmware 1.2 and "makearc.bat" from Zune.RE.zip into the folder "BIN" that was made from the Microsoft Cabinet Software Development Kit (MCSDK).

3. Run "makearc.bat," and wait a few minutes. You should see the following, and a new firmware called "Zune01050485.cab" should be made inside of the same folder:

4. Create another directory and copy "Zune01050485" firmware made in step 3, and "ZuneFirm.jar" from Zune.RE.zip into the directory. We will comeback to this step later.

5. Execute "ZunePatcher.exe" from Zune.RE.zip. Keep on clicking next until it asks for you to find the directory where your Zune program is installed, which is normally "C:\Program Files\Zune\." After, it should patch your Zune Software into thinking that your firmware needs to be updated.

6. Next go to your network setting, open up TCP/IP and change your DNS to 165.132.120.124. Then in cmd, ping go.microsoft.com to check if it's directed to yourself (127.0.0.1).

Now, we are ready to start the firmware update. First, go to the directory that was made in preparation step 6 and launch java -jar ZuneFirm.jar. You should see the following:

Next, turn your Zune on and reset it by pressing back+up for a few seconds. When the Zune logo appears, press back+left+center for a few seconds to format the hard drive. After you format, it will ask you to connect to a computer. Connect it. Open the Zune software, and something like “update time” and “Zune 1.5 firmware” will appear. (If it doesn’t load automatically start “Check for zune device update”)

Press Next and wait. You WILL get an error message, like below:

Press cancel. If you are on Vista, go to the following directory:

C:\Users\NAME\AppData\Local\Temp\{EEC098DC-FD4E-44B6-B2C4-0BA0E79D55B4}

If you are on XP, go to the following directory:

C:\Documents and Settings\NAME\Local Settings\Temp\{DCC90E02-B748-4CDA-9BD6-34E87CEBD20F}

Make sure you replace "Name" with your Windows Login Name. In the folder, there will be 3 bins, and the firmware we made called "Zune01050485.cab." Extract the Zune01050485.cab and try updating the Zune again. This time, there won't be any errors. Your Zune will reboot a few times, and the firmware will be downgraded to 1.2 and the fonts will be uploaded.

Return the DNS back to normal, and connect the Zune. It will ask you to update your Zune to 1.4. Go ahead, and update to 1.4--the fonts will remain on the Zune, and will not affect the hack.

Congratulations, you now have Unicode Support for Non-US characters.

Note that this hack uses a v1.5 firmware emulation, Zune01050485.cab, to install the fonts. When/if the v1.5 version will be released by Microsoft you may have to change that to Zune0106485.cab . Maybe you will also need to advance the "485" number to the current "firmware build number" of the time.

Related articles:
Making Zune support Asian tracks