How to do a date countdown (to a future date)?
The Countdown module has a drupal 6 &amp; 7 version. This may work for you. Here is a quote about it (from the module's project page):

Adds a block titled &quot;Countdown&quot; to count the days, hours, minutes, and seconds since or until a specified event. Can configure to just show days, or days and hours, etc.
See also:

jQuery Countdown.
jQuery Countdown Timer.