I have a WordPress 3 Multisite setup with 2 sites. blog1 is the main site, and blog2 is a subdirectory of blog1.
I have created a menu in blog one that I can call using wp_nav_menu, now in blog2 I want to show that same menu linking to blog1. Is there a built in way to do this?
You can import links from one blog to another.
http://en.support.wordpress.com/blogroll/import-export-links/
If this is not what you want, please clarify.
I don’t think there is a way to do this built into WordPress. What you can do, however, is create a page that show this menu on the first blog and then include it on the other blog by URL using
echo file_get_contents('http://www.firstblog.com/page');