Something

	// function to convert 12 hour time to 24 hour
	// $time = hh:mm AM/PM
	function transTime($time)
	{
		list($h,$m) = explode(':',$time);
	
		$h = (int)$h;
		$m = (int)$m;
	
		if(substr($time,strlen($time)-2) == 'PM')
			$h += 12;
	
		return str_pad($h,2,'0',STR_PAD_LEFT).':'.str_pad($m,2,'0',STR_PAD_LEFT);
	}

	echo '<p>'.transTime('11:52 AM').'</p>';
	echo '<p>'.transTime('08:32 AM').'</p>';