[noppid]

Try this.

in the register templates add...
<tr>
<td bgcolor="{firstaltcolor}"><normalfont><b>Join our mailing list?</b></normalfont><br>
<smallfont>Selecting yes will add you to our mailing list.</smallfont></td>
<td bgcolor="{firstaltcolor}"><normalfont>
<input type="radio" name="wantsmail" value="yes"> yes
<input type="radio" name="wantsmail" value="no" checked> no
</normalfont></td>
</tr>

in register.php at around line 350 add

$maillist=iif($wantsmail=="yes",1,0);

then wrap the append code in an if()...

if($maillist) {
$fp = fopen("emails.txt", "a");
fwrite($fp, "$email\r\n");
fclose($fp);
}

This is not tested.