WordPress 3 menus in you wordpress theme

Since wordpress 3 they have introduced a custom menu option which is something I really missed in the wordpress versions. But unfortunately this requires a bit of code change for out dated themes. This tutorial will show you in simple steps how you can add your own menus for wordpress themes.
In a nut shell, wordpress allows you to define the locations for your custom menus. If you have not defined these menu locations you will most likely see a message in the administrator stating that the theme doesn’t support menus.
Step 1 – Modifying your functions.php
In order for wordpress to recognize a menu location, it has to register with the system at run time. You can do this by creating a custom function as follows.

Single menu

function register_my_menus() {
register_nav_menus(
array(
'header-menu' => __( 'Header Menu' )
);
}

Multiple menus

function register_my_menus() {
register_nav_menus(
array(
'header-menu' => __( 'Header Menu' ),
'extra-menu' => __( 'Extra Menu' ))
);
}

The register_nav_menus() function let you register multiple locations in your theme for menus. If you require more than one menu you can simply add more elements as shown above. The ‘header-menu’ refers to the tag which is used to recognize the menu in the theme and ‘Header Menu’ is just a display name in your admin area.
Since this is a custom function you have to make sure that wordpress runs this function at start every time when someone comes to the site. This is achieved through the use of add_actions() function.
add_action( ‘init’, ‘register_my_menus’ );
This function tells wordpress to run the register_my_menus() function after wordpress has finished loading but before any headers are sent. Once both of these are in place wordpress will now know that the theme has a location called ‘Header Menu’ in its theme for menu placement.
Step 2 – Adding the location to your theme
You can easily add the location by writing the following line of code on the location where you need to add the menu.
<?php wp_nav_menu(  array( ‘theme_location’ => ‘header-menu’ ));  ?>
This simply tells the system to add the menu registered to ‘header-menu’ at this location. But personally I would say use a safety check before adding this. Because if for any chance your register_my_menus() function doesn’t work you will end up without a menu for your site.  There for you can do the following.

if(function_exists(' register_my_menus’)) {
wp_nav_menu(  array( 'theme_location' => 'header-menu' ));
} else {
wp_list_pages('hide_empty=0&title_li=');
}

This initially checks if your function ‘register_my_menus’ was registered successfully or not. If it was successful then the uses will see your custom menu. If not they will end up seeing your standard menu.

Step 3 – Customizing the menu
Now all you need to do is login in to your admin area and customize the menu in Appearance -> menu section.