I have some source files that have comments written in Japanese. When I open these files in Visual Studio they appear like this:
à–¾FNCAP‰¹—p‚̃XƒŒƒbƒh
Have you turned on support for Eastern languages for Windows? I have that turned on and I can see Chinese characters in Visual Studio 2005 on WinXP.
To turn it on you'll probably need the installation DVD for Windows. The setting is under Regional and Language Options in the Control Panel. I think you just need to check the "Install files for East Asian languages" option.
Microsoft's support page for internationalization has some screenshots and instructions.