edit news.tpl and comment out this bit:
<form action="news.php" name="subscribeform" method="post">
<input type="hidden" name="subscribe_lng" value="{$store_language}" />
<table>
<tr>
<td>
{$lng.lbl_your_email}
<br />
<input type="text" name="newsemail" size="16" />
<br />
{include file="buttons/subscribe_menu.tpl"}
</td>
</tr>
</table>
</form>