Lout - A document formatting system designed and implemented by Jeffrey Kingston, producing output in PostScript. C source code for Unix under GPL. - http://snark.niif.spb.su/~uwe/lout/lout.html
IRun RTF Converter - A Windows utility for converting RTF documents conforming to the RTF1.5 Specifications to XML or HTML. - http://www.pilotltd.com/irun/