An easy way to add an external link is to add it to the end of the nav <ul> like this:
More than that requires a plugin. I think the i18n plugin allows you to add links to your menu but i have never used it.
PS Carlos' redirect plugin, new today will let you add a menu entry, see
http://get-simple.info/forums/showthread.php?tid=5070
Code:
<nav id="nav">
<ul>
<?php get_navigation(return_page_slug()); ?>
<li><a href="http://nedomain.com/forum" title="External link to Forum">Forum</a></li>
</ul>
</nav>
More than that requires a plugin. I think the i18n plugin allows you to add links to your menu but i have never used it.
PS Carlos' redirect plugin, new today will let you add a menu entry, see
http://get-simple.info/forums/showthread.php?tid=5070