ho modificato il tuo codice inserendo due div con "float:left" e impostando l'altezza a 20px si al campo input che al bottone invia......dimmi se funziona, l'ho fatto al volo....
Codice PHP:
<tr>
<td>
<?php
$info_box_contents = array();
$info_box_contents[] = array('text' => BOX_HEADING_SEARCH);
new infoBoxHeading($info_box_contents, false, false);
$info_box_contents = array();
$info_box_contents[] = array('form' => tep_draw_form('quick_find', tep_href_link(FILENAME_ADVANCED_SEARCH_RESULT, '', 'NONSSL', false), 'get'),
'align' => 'center',
'text' => '<div style="float:left;height:20px;">'.tep_draw_input_field('keywords', '', 'size="0" maxlength="30" style="width: ' . (BOX_WIDTH-13) . 'px"') . '</div>' . tep_hide_session_id() . '<div style="float:left;height:20px;">' .tep_image_submit('cerca.gif', BOX_HEADING_SEARCH) . '</div>
' . BOX_SEARCH_TEXT . '
[url="' . tep_href_link(FILENAME_ADVANCED_SEARCH) . '"][b]' . BOX_SEARCH_ADVANCED_SEARCH . '[/b][/url]');
new infoBox($info_box_contents);
?>
</td>
</tr>