Open man pages in Firefox like in Konqueror
First, I found what looked like the right software, Bwana, but it just works in Apple OS X, not in Linux.
I knew a long time ago I had tried man2html, which uses cgi scripts to render man pages in the browser on the fly, but you still couldn't type something like "man rsync" in the location box and load that man page right away, you have to load man2html homepage and type your search there.
Luckily, I already knew how to create "intelligent" search bookmarks using the "%s" variable and bookmarks keywords, so now I can have the functionality I wanted by just typing "man program".
First, install man2html and apache; then in Firefox create a bookmark with location = "http://localhost/cgi-bin/man/man2html?query=%s" and keyword = "man". Now try it: type "man gedit". Wonderful!