Take a look the discussion on
Colors in a console.
You'll need to know the escape sequence to encode colors, and how to install ansi.sys on your system. The page linked points to some information, at least for NT. For 95/98/ME systems, where it is easier, it might be covered in the system documentation under "ANSI.SYS" or "CONFIG.SYS". Also, look at books on DOS in your neighbor's collection of books-too-old-to-use-but-too-expensive-to-throw-away.