如何更改用户发布内容时mysql时间戳的格式

Currently whenever the timestamp is echo'ed it looks like this

function show_posts($userid){
$posts = array();
$sql = "select body, stamp from posts where user_id = '$userid' order by stamp desc";
$result = mysql_query($sql);
while($data = mysql_fetch_object($result)){
    $posts[] = array(   'stamp' => $data->stamp, 
                        'userid' => $userid, 
                        'body' => $data->body
                );
}
return $posts;
}

i want to take this stamp and change it so instead of printing 2012-03-26 12:07:52 it will print the day followed by the time etc. below is how i show it on my webpage.

<?php
        foreach ($posts as $key => $list){
            echo "<tr valign='top'>
";
            echo "<td>".$list['userid'] ."</td>
";
            echo "<td>".$list['body'] ."<br/>
";
            echo "<small>".$list['stamp']."<br/>
 <a>Like</a> <a>Flag</a><hr     class='span9'/></small></td>
";
            echo "</tr>
";
        }
?>

Use strtotime to convert the string to a timestamp, then use date to format it how you want.

Use date_format().