[Help] Register.php That ask for Email

<?php
include('config.php');
?>
<script type="text/javascript" src="./inc/md5.js"></script>
<form method='post' action='register.php?act=register'>
<b><strong>Please make sure you remember your Account ID and Password</strong></b><hr>
<tr><td><table width="100%" border="0" cellspacing="0" cellpadding="0">
<tr><td width="64" valign="top"></td>
<td valign="top">
<table width="100%" border="0" cellspacing="10" cellpadding="0">
<tr><td><strong>Account ID:</strong></td>
<td width="66%"><input type="text" size="30" maxlength="15" name="id" id="id" title="* Only 4-15 Words/number"></td></tr>
<tr><td><strong>Password:</strong></td>
<td><input class=it id="ipassword" type="password" size="30" maxlength="15" name=pass title="* Only 4-15 Words/number"></td></tr>
<tr><td><strong>Retype Password:</strong></td>
<td><input class=it1 id="ipassword" type="password" size="30" maxlength="15" name=retpass title="* Only 4-15 Words/number"></td></tr>
<tr><td><strong>Email</strong></td>
<td width="66%"><input type="text" size="30" maxlength="30" name="email" id="email" title="* Use a valid email"></td></tr>
</table>
</td>
</tr>
</table>
</td>
</tr>
<br /><br />
<TABLE align="center">
<tr><td align="center"><input type="hidden" name="hash"><input class=Butt type=submit onclick="hash.value = login(pass.value)" value='register' name=B1></td></tr>
</table>
</td>
</tr>
</table>
</form>
</td>
</tr>
</table>
<?php
                        if($_GET['act'] == "register")
                                {
                                        mysql_select_db($mydbacc);
                                        $userid = trim($_POST['id']);
                                        $password=trim($_POST['pass']);
                                        $passretype=trim($_POST['retpass']);
                                        $hash=$_POST['hash'];
					$_SERVER['REMOTE_ADDR'];
                                        $email = $_REQUEST['email'];
                                         if($userid=="" || $password=="" || $passretype=="" )
                                         {
                                                echo "<center>You must fill all information in the Required Field!</center>";
                                         }
                                         else
                                         {
                                             if($password == $passretype)
                                                 {
                                                  if(!ereg("^[0-9a-z]{4,15}$",$userid))
                                                  {
                                                        echo "<center>Only letters and numbers only are allowed.Long 4 to 15 words</center>";
                                                        }
                                                        else
                                                        {
                                                                $res = mysql_query("select * from account where name = '".$userid."' order by id desc");
                                                                if(mysql_num_rows($res) == 0)
                                                                {
                                                                        mysql_query("insert into account (name,Password,Reg_date,netbar_ip,email) values ('".$userid."','".$hash."','".date("y-m-d H:i:s", time())."','".$_SERVER['REMOTE_ADDR']."','".$email."')");
									echo "<center>Account successfully registered!</center>";
                                                                }
                                                                else
                                                                {
                                                                        echo "<center>This account has been registered, please select another!</center>";
                                                                }
                                                        }
                                                }
                                                else
                                                {
                                                        echo "<center>Password authentication is not the same as your Password</center>";
                                                }
                                        }
                                }
                        ?>

`email` varchar(32) default NULL,