Código PHP:
<?
include "../includes/config.php";
mysql_connect($server, $db_user, $db_pass) or die (mysql_error());
$result = mysql_db_query($database, "select * from $table WHERE username = '$username'") or die (mysql_error());
$qry = mysql_fetch_array($result);
?>
<input type="text" class="register" name="email" value="<?php echo $qry[email]; ?>" />