GNU Enscript is a free replacement for Adobe's enscript program. GNU Enscript converts ASCII files to PostScript, HTML or RTF and stores generated output to a file or sends it directly to the printer. It includes features for pretty-printing (language-sensitive code highlighting) in several programming languages. Enscript can be easily extended to handle different output media and it has many options that can be used to customize printouts.

See also http://www.markkurossi.com/genscript/
The GnuWin32 project has a version for Windows at http://gnuwin32.sourceforge.net/packages/enscript.htm

Operating Systems: Linux, BSD, Mac OSX, Windows, Windows 9x