while matt's idea is brilliant, it is sort of outdated now that you can build custom menus in WP3.0
http://themeshaper.com/forums/topic/a-better-way-to-use-the-new-menu-in-wordpress-30-final-version#post-13265
http://justintadlock.com/archives/2010/06/01/goodbye-headaches-hello-menus
in terms of 2 menus i had this on a test blog that never got finished :
/* ********************************************** */
/* MENUS */
/* ********************************************** */
// We declare that our theme supports wp_nav_menu()
add_theme_support( 'nav-menus' );
// We Register the a new menu for the theme called "Primary Menu"
function register_my_menus() {
register_nav_menus(
array(
'primary-menu' => __( 'Primary Menu' ),
'secondary-menu' => __( 'Secondary Menu' ),
)
);
}
add_action( 'init', 'register_my_menus' );
// We remove the standard Thematic menu
function remove_menu() {
remove_action('thematic_header','thematic_access',9);
}
add_action('init', 'remove_menu');
// We create the new wp_nav_menu called "Primary Menu" in our theme
function child_access() { ?>
<div id="access">
<div class="skip-link"><a href="#content" title="<?php _e('Skip navigation to the content', 'thematic'); ?>"><?php _e('Skip to content', 'thematic'); ?></a></div><!-- .skip-link -->
<?php /* Our navigation menu. If one isn't filled out, wp_nav_menu falls back to wp_page_menu. The menu assiged to the primary position is the one used. If none is assigned, the menu with the lowest ID is used. */ ?>
<?php
wp_nav_menu( array(
'theme_location' => 'primary-menu', // we define this as being the previously registered "Primary Menu"
'menu_class' => 'sf-menu', // we assign the sf-menu class to the menu ul so that superfish workds
'container_class' => 'menu', // we assign the menu class to the menu container div so to keep it compatible with the Thematic menu styling
//'fallback_cb' => '',
));
?>
</div><!-- #access -->
<?php
}
add_action('thematic_aboveheader','child_access');
function secondary_menu() {
if ( has_nav_menu( 'secondary-menu' ) ) { ?>
<div id="nav-container">
<?php wp_nav_menu( array( 'theme_location' => 'secondary-menu',
'menu_class' => 'sf-menu', // we assign the sf-menu class to the menu ul so that superfish workds
'container_class' => 'menu', // we assign the menu class to the menu container div so to keep it compatible with the Thematic menu styling
) ); ?>
</div>
<?php }
}
add_action('thematic_belowheader','secondary_menu');
it worked as far as i can recall. but i doubt it is the most elegant code you will ever see. you mileage may definitely vary.