een form naar de zelfde pagina laten gaan

Ik heb een vraag over hoe ik een form in de onderstaande pagina kan inbrengen, zodat die ook nog procest in dezelfde pagina, en dan direct terug uitkomt bij die pagina waar dan nu de inhoud van dat form staat. Het form dient voor comments onder een nieuwsitem te zetten.
Het form zou er zo moeten uitzien:


<form methode="POST" action=" ZIE VRAAG! ">
Author:<br>
<input type="text" name="commentwriter" size="60"><br>
Message:<br>
<textarea name="content" rows="10" cols="60"> </textarea><br>
<input type="submit" name="submit" value="Submit" size="20">
</form>


De hele php-code van de pagina:

<?
require('config.php');
if (!@mysql_select_db("$db_database", @mysql_connect("$db_host", "$db_username", "$db_password")))
{
echo 'Er kan geen database connectie gemaakt worden.';
exit();
}
if((!$_REQUEST['newsid']) && (!$_REQUEST['readmore'])){
$sql = "SELECT * FROM news WHERE visible = 1 order by newsid DESC";
$res = mysql_query ($sql) or die (mysql_error ());
if (mysql_num_rows ($res) >= 1){
while ($row = mysql_fetch_array ($res)){
echo'
<table border="0" cellspacing="0" cellpadding="5" id="phpnieuws_inside" width="430">
<tr>
<td width="430" id="title">
<font face="Verdana" size="2"><b>' . $row['newstitle'] . '</b></font><br>
<i><font face="Verdana" size="1">By: ' . $row['newswriter'] . '</font></i>
</td>
</tr>
<tr>
<td width="430" id="news_short">
<font face="Verdana" size="2">' . $row['news_short'] . '</font>
</td>
</tr>
<tr>
<td width="430" id="comments">
<p align="right"><font face="Verdana" size="2">|<a href="index.php?newsid=' . $row['newsid'] . '&readmore=1" style="text-decoration: none">Read More</a></font></p>
</td>
</tr>
</table><br><br>';
}
}
} else {
$newsid = $_REQUEST['newsid'];
$sql = 'SELECT * FROM news WHERE newsid = \''.$newsid.'\'';
$res = mysql_query($sql);
$row = mysql_fetch_row($res);
$res = mysql_query ($sql) or die (mysql_error ());
if (mysql_num_rows ($res) >= 1){
while ($row = mysql_fetch_array ($res)){
echo'
<table border="0" cellspacing="0" cellpadding="5" id="phpnieuws_inside" width="430">
<tr>
<td width="430" id="title">
<font face="Verdana" size="2"><b>' . $row['newstitle'] . '</b></font><br>
<i><font face="Verdana" size="1">By: ' . $row['newswriter'] . '</font></i>
</td>
</tr>
<tr>
<td width="430" id="news_short">
<font face="Verdana" size="2" color="#9E9E9E"><i>' . $row['news_short'] . '</i></font>
</td>
</tr>
<tr>
<td width="430" id="news_short">
<font face="Verdana" size="2">' . $row['news_long'] . '</font>
</td>
</tr>
</table><br><br>
<img src="images/commentline.gif" border="0">';
}
}
$newsid=$_GET[newsid];
$mysql_id = mysql_connect("$db_host", "$db_username", "$db_password");
mysql_select_db("$db_database",$mysql_id);
$sql="SELECT * FROM comments WHERE newsid='$newsid'";
$res = mysql_query("$sql", $mysql_id);
$row = mysql_fetch_row($res);
$res = mysql_query ($sql) or die (mysql_error ());
if (mysql_num_rows ($res) >= 1)
{
while ($row = mysql_fetch_array ($res))
{
echo'

<table border="0" cellspacing="0" cellpadding="0" id="comments" width="430">
<tr>
<td width="5" bgcolor="#D2D2D2">
</td>
<td width="425" id="name" bgcolor="#D2D2D2" height="10" valgin="top">
<font face="Verdana" size="2">By <u>' . $row['commentwriter'] . '</u></font>
</td>
</tr>
</table>
<table border="0" cellspacing="0" cellpadding="3" id="commentstext" width="430">
<tr>
<td width="430" id="text">
<font face="Verdana" size="2">' . $row['commenttext'] . '</font>
</td>
</tr>
</table>
<br><br>
<p align="center"><a href="postcomment.php?newsid=' . $row['newsid'] . '" style="text-decoration: none"><font face="Verdana" size="2" color="#000000"><u>Post Comment</u></font></a></p>';}}
else {
echo '<table border="0" cellspacing="0" cellpadding="5" id="nocomment" height="10" width="430">
<tr>
<td width="430">
<font face="Verdana" size="2" color="#000000">No comments on this item yet!</font>
</td>
</tr>
</table>
<p align="center"><a href="postcomment.php?newsid='.$newsid.'" style="text-decoration: none"><font face="Verdana" size="2" color="#000000"><u>Post Comment</u></font></a></p>';
}
}
?>



Dat form zou op de 2 plaatsen moeten komen waar de link "postcomment.php?newsid='.$newsid.'" als "Post Comment" beschreven staat.

Hoe kan ik dit doen?
Kan iemand aub hier een stukje code met dat form en dan de verwerking en verdere afloop ervan posten?

Mvg. Jens