source: http://texblog.wordpress.com/2011/05/02/date-and-time/
\usepackage[option (see below)]{datetime}\currenttime prints the actual time (hh:mm by default).
\settimeformat{...} with one of the following arguments:
xxivtime Twenty-four hour time, e.g. 22:28 (default).
hhmmsstime Twenty-four hour time, e.g. 22:28:00.
ampmtime Twelve hour time, e.g. 10:28pm.
oclock Displays the current time as a string - my favorite for 'version in progress'