Or, plugin using locationprocess_templates_complete
PHP Code:
$template_hook['navtab_end'] .= '<li><a class="navtab" href="/frontpage.html">Front Page</a></li>' ;
$template_hook['navtab_end'] .= '<li><a class="navtab" href="http://page.com/twitterpage.html">Twitter Page</a></li>' ;
$template_hook['navtab_end'] .= '<li><a class="navtab" href="http://page.com/facebookpage.html">Facebook Page</a></li>' ;