Currently, Sublime Text doesn't support multi-byte encodings. Files with CJK encodings will become a mess. So, I write a plug-in to solve this problem.
The plug-in will detect the encoding when opening files, and convert its content to UTF-8 for viewing and editing. It will convert the file back to its original encoding when saving.
Addtional, you can translate between different encodings by using its "Set File Encoding to" menu entry. For example, you can open a UTF-8 file, and save it to GBK, and vice versa.
CJK encodings including GBK, BIG5, EUC_KR, EUC_JP have been tested.
You can install this plug-in via Package Control (by searching "ConvertToUTF8").
More infomation: https://github.com/seanliang/ConvertToUTF8