Pandoc is a command-line tool for converting from one markup format
to another.  It can read markdown and (subsets of) reStructuredText,
HTML, and LaTeX, and it can write markdown, reStructuredText, HTML,
LaTeX, DocBook, RTF, and S5 HTML slide shows.

Pandoc extends standard markdown syntax with footnotes, embedded LaTeX,
and other features.  A compatibility mode is provided for those who
need a drop-in replacement for Markdown.pl.  Included wrapper scripts
make it easy to convert markdown documents to PDFs and to convert web
pages to markdown documents.

In contrast to existing tools for converting markdown to HTML, which
use regex substitutions, pandoc has a modular design: it consists of a
set of readers, which parse text in a given format and produce a native
representation of the document, and a set of writers, which convert
this native representation into a target format. Thus, adding an input
or output format requires only adding a reader or writer.

WWW: http://sophos.berkeley.edu/macfarlane/pandoc/