did you try putting the <center></center> tags?
ACP -> Templates -> *Template Name* -> "Index Page Templates" -> index
find
Quote:<tr><td valign="top" align="right">
<span class="smalltext">$logoutlink<a href="misc.php?action=markread">$lang->markread</a> | <a href="showteam.php">$lang->forumteam</a> | <a href="stats.php">$lang->forumstats</a></span>
</td></tr>
replace with:
Quote:<tr><td valign="top" align="center">
<span class="smalltext">$logoutlink<a href="misc.php?action=markread">$lang->markread</a> | <a href="showteam.php">$lang->forumteam</a> | <a href="stats.php">$lang->forumstats</a></span>
</td></tr>