This program has been replaced by PostScriptToPDF for Windows. If you still want it, you may download it from the link below. Details of how to use it are on the page for the new version.
GSDistller is a Windows utility that converts PostScript printer files to PDF format using only open-source software. You may download it here. The program is designed for use either from the Windows command line or by dropping a file on the application.
Edward Mendelson (edward [dot] mendelson [at] columbia [dot] edu)