I am happy to announce the immediate availability of Markdown2Html tool (as part of the WizTools.org mini-projects). Guess what, this is a command line tool written in Java used to convert Markdown text to HTML. The tool operates on STDIN and STDOUT. Sample usage:
$ java -jar markdown2html-0.1.0-jar-with-dependencies.jar < sample.md > out.html
Download the executable Jar: http://wiztools.googlecode.com/files/markdown2html-0.1.0-jar-with-dependencies.jar.