/ Published in: PHP
I've been using a Javascript to do the same thing for years but have always wanted to do the same thing in PHP -- just never got around to writing it. Fortunately, ScriptyGoddess did it for me. Haven't actually implemented it but it looks like it should work.
URL: http://www.scriptygoddess.com/archives/2002/05/23/count-up-timer-in-php/