are those between domestic product(in US) and international product same?

Because these are user forums, none of us are connected with Apple. We don't know the information required to answer your question. If you are concerned, then you should ask a person with expertise in the Apple Store such as the general manager or head technician.

These are the standard languages that can be selected in the standard version of Mac OS X (after 10.7.3):

The Finder and applications included with Mac OS X v10.1 or later can display menus and dialog text in any of these languages:

• English
• Japanese
• French
• German
• Spanish
• Italian
• Portuguese
• Portuguese (Portugal) -- Mac OS X v10.5 or later only
• Dutch
• Swedish
• Norwegian Bokmål
• Danish
• Finnish
• Russian -- Mac OS X v10.5 or later only
• Polish -- Mac OS X v10.5 or later only
• Chinese (Simplified)
• Chinese (Traditional)
• Korean
• Arabic -- OS X Lion v10.7 or later only
• Czech -- OS X Lion v10.7 or later only
• Hungarian -- OS X Lion v10.7 or later only
• Turkish -- OS X Lion v10.7 or later only
• Thai -- OS X Lion v10.7.3 or later only
• Catalan -- OS X Lion v10.7.3 or later only
• Croatian -- OS X Lion v10.7.3 or later only
• Greek -- OS X Lion v10.7.3 or later only
• Hebrew -- OS X Lion v10.7.3 or later only
• Romanian -- OS X Lion v10.7.3 or later only
• Slovak -- OS X Lion v10.7.3 or later only
• Ukrainian -- OS X Lion v10.7.3 or later only

from:

OS X: Changing the language shown in menus and dialogs - Apple Support

As far as i can see (and i do not speak for Apple) the only other thing you need is the additional Korean graphics on the keyboard. If yours does not come with the correct extra characters (in addition to English), a sharpie pen (fine-tipped marker) could fix that in a few minutes.

In addition to that, the only thing that has to be different for a different country is the AC end of the power cord (which is replaceable), to fit in the local power outlets.

BranHa wrote:

when i buy Macbook in any other countries, is it same product to buy in Korea and the U.S??(i know keyboard is different, plus with Korean keyboard ).

Yes.

I think prices can be quite different depending on the country, however. Apple stores do not ship outside their own country.