I would probably do it with mktime getting the EPOCH time for the two dates and calulating the difference in seconds, working from there.
Something like:
<?php
$startHour=0;
$startMinute=0;
$startSecond=0;
$startDay=12;
$startMonth=1;
$startYear=2009;
$finishHour=0;
$finishMinute=0;
$finishSecond=0;
$finishDay=2;
$finishMonth=5;
$finishYear=2010;
$startTime=mktime($startHour, $startMinute, $startSecond, $startMonth, $startDay, $startYear);
$finishTime=mktime($finishHour, $finishMinute, $finishSecond, $finishMonth, $finishDay, $finishYear);
$seconds_difference = $finishTime - $startTime;
$minutes_difference = round($seconds_difference/60,0);
?>
HTH.
Cheers,
Dave.
