Thread Location: http://www.tforumhacks.com/tforum/viewtopic.php?TopicID=635

add this function to functions.php

function TimeDifference($timestamp)
{	global $txt;
	$difference = time() - $timestamp;
	$secs = $difference % 60;
	$difference = intval($difference / 60);
	$mins = $difference % 60;
	$difference = intval($difference / 60);
	$hours = $difference % 24;
	$days = intval($difference / 24);
	$TimeDifference = $txt["timeago"];
	$TimeDifference = str_replace("XD",$days,$TimeDifference);
	$TimeDifference = str_replace("XH",$hours,$TimeDifference);
	$TimeDifference = str_replace("XM",$mins,$TimeDifference);
	$TimeDifference = str_replace("XS",$secs,$TimeDifference);
	return $TimeDifference;
}


add the following line to english_lg.php (and every other language file you hav installed)

$txt["timeago"] = "XD days, XH hours, XM minutes, XS seconds ago";

you can alter this string to get the format you want. XD, XH, XM and XS will be replaced with the right numbers.

whereever you want a time difference instead of a absolute time use

TimeDifference(...)

instead of

FormatDate(...,$CurrentUserInfo[timezone])

and

FormatTime(...,$CurrentUserInfo[timezone])