I know of XSL:FO to PDF, but not Postscript... I'm sure something for that exists though:
As for XML to HTML, just save the output of the XSLT transformation. If you want to do it outside of a browser, you can grab (and build) Transformiix from the Mozilla project's CVS, or you could get Apache's Xalan:
Or I'm sure you could whip out Visual Studio and write a quick program to do that using MSXML.