then the menu_principal.php page would only contain this.
<table width="487" border="0" cellspacing="0" cellpadding="0" height="26">
<tr>
<td align="center">InÃcio</td>
<td align="center">Tarot Online</td>
<td align="center">Consultório</td>
<td align="center">F.A.Q.</td>
</tr>
</table>
any css on that page should wither be in the parent page or in an external .css file.
that being said, you should also edit this line to match this:
<td width="487" height="26" background="images/tarotcctemplate_CORTADO_LAYOUT_02-03.png"> <?php include "menu_principal.php" ?></td>
also, the use of tables should be for tabular data, not the overall layout of your markup, use lists instead.