Take a look to the demostration. This countdown has a great animation.

This project is still at beta stage, soon i'll implement callbacks and stuff.

Basic usage:

  $('#counter').countdown({startTime: "01:12:32:55"});

Complete usage:

  $('#counter').countdown({
    stepTime: 60,
    format: 'hh:mm:ss',
    startTime: "12:32:55",
    digitImages: 6,
    digitWidth: 53,
    digitHeight: 77,
    timerEnd: function() { alert('end!!'); },
    image: "digits.png"
  });

Did I mention that js code weighs just 1.7 KB?

See the demo!!.