Multibyte character sets (MBCS) are an alternative to Unicode for supporting character sets, like Japanese and Chinese, that cannot be represented in a single byte. If you are programming for an international market, consider using either Unicode or MBCS, or enabling your program so you can build it for either by changing a switch.
The most common MBCS implementation is double-byte character sets (DBCS). Visual C++ in general, and MFC in particular, is fully enabled for DBCS.
For samples, see the MFC source code files.