The following function will convert the time stamp to time ago like 1hour ago, 1day ago, 2days ago etc.

PHP Code

<?php
function timeAgo($time_ago){
  $cur_time 	= time();
  $time_elapsed = $cur_time - $time_ago;
  $seconds 	= $time_elapsed ;
  $minutes 	= round($time_elapsed / 60 );
  $hours 		= round($time_elapsed / 3600);
  $days 		= round($time_elapsed / 86400 );
  $weeks 		= round($time_elapsed / 604800);
  $months 	= round($time_elapsed / 2600640 );
  $years 		= round($time_elapsed / 31207680 );
  // Seconds
  if($seconds <= 60){
     echo "$seconds seconds ago";
   }
   //Minutes
   else if($minutes <=60){
	 if($minutes==1){
		echo "one minute ago";
	 }
	 else{
		echo "$minutes minutes ago";
	 }
    }
    //Hours
   else if($hours <=24){
	if($hours==1){
		echo "an hour ago";
	}else{
		echo "$hours hours ago";
	}
    }
    //Days
    else if($days <= 7){
	if($days==1){
		echo "yesterday";
	 }else{
		echo "$days days ago";
	 }
    }
    //Weeks
   else if($weeks <= 4.3){
	if($weeks==1){
		echo "a week ago";
	}else{
		echo "$weeks weeks ago";
	}
   }
   //Months
   else if($months <=12){
	if($months==1){
		echo "a month ago";
	}else{
		echo "$months months ago";
	}
   }
   //Years
  else{
	if($years==1){
		echo "one year ago";
	}else{
		echo "$years years ago";
	}
   }
}
?>

Call in action

<?php
  $curenttime="2013-07-10 09:09:09";
  $time_ago =strtotime($curenttime);
  echo timeAgo($time_ago);
?>

Output

10 years ago