Well this is a bit of a tricky one and while the solution (without coding in new features) is a bit of a hack, I enjoyed figuring this one out.

Step one, grab the id of the Submit link on the page. In my case i looked at the html output (right click page and view source) and it is 'dnn_ctr366_CFD_cmdSend'
Tip: search for CFD_cmdSend" class="CommandButton"   and you should be right on it, its the ID value eg: ID="dnn_ctr366_CFD_cmdSend"

Step two is going to the Configure Look and Feel area of the module and setting the Send text to nothing (blank)

Step three is to replace the form items html with the following:
Note: replace the item in bold with you ID on YOUR form.

<table width="250" cellspacing="0" cellpadding="1" border="0">
    <tbody>
        <tr valign="top" class="SubHead">
            <td style="white-space:nowrap" width="100%">[ITEMNAME]</td>
            <td>[ITEM]</td>
            <td>&nbsp;[REQITEM]</td>
            <td style="white-space:nowrap">&nbsp;<a href=" goSubmitForm()">Newsletter Signup!</a></td>
        </tr>
    </tbody>
</table>
<script language="javascript">
    function goSubmitForm()
    {
        window.location = document.getElementById('dnn_ctr366_CFD_cmdSend').href;
    }
</script>


Now that your Form Items Layout html is as above, you should now have no submit button below but instead to the right hand side. When the right hand side button is click it will pull the action from the hidden original submit button and process the form.