xmlmantohtml file.1.xml > file.1.html
xmlmantohtml is a small script to convert xml/man to html.
You will find the dtd in /usr/share/xmltoman/ on a debian system. There is also an xsl file to generate html using xsltproc(1). See also /usr/share/doc/xmltoman/examples for examples.
If xsltproc proves to be a useful alternative, this program will be obsoleted.
xmltoman was written by Oliver Kurth <email@example.com>