I am working on my first serious WordPress MU installation in a couple of years, and I came across an interesting question:  How do I use the main home page navigation across all blogs?  Basically, I need the main navigation to be the same on every blog.

After some research, I came upon this discussion thread on the WordPress forums.  In the thread, you will see all sorts of different solutions proposed from plugins to hooks.  The simplest solution that I found is to include the following in your sub-blog’s “header.php” file:

<?php switch_to_blog(1); ?>
<?php wp_list_pages('title_li='); ?>
<?php restore_current_blog(); ?>

This code temporarily switches back to the main blog’s information, pulls the main navigation, then switches back to the current blog.  Pretty nifty!