A lot of people wanted to know the technique for adding a Drop Down Menu to their WordPress themes. So, here is a quick way to do this. This tweak will let you create menus, sub-menus and sub-sub-menus and it applies to your pages, categories and archives.
Download the Suckerfish Dropdown Menu for WordPress. Even if you have installed WordPress 2.5 recently, this plugin works perfectly. Extract the plugin and put the files in your wp-content/plugins folder. Activate the plugin from your wp-admin section.
Now, open your existing theme folder which you have applied to your WordPress installation. Most probably, you already have a navigation menu in the theme (most themes have it in the header.php file). So, just replace your existing menu code with this command :-
<?php suckerfish(); ?>
Save and close the file.
This is the final step. Go to this online Suckerfish Dropdown CSS Generator, where you can generate a custom CSS file for your menu and copy it to your clipboard. Now go to your wp-admin and click on the Suckerfish option which you can find under the options menu (in WP 2.3) or the settings menu (WP 2.5). Paste the custom CSS information where it says “Enter your CSS here”. It might show something like #222 in the box which you can safely remove. The plugin also gives you options to choose the menu items that you want to display in the menu.
To test the functionality of this drop down menu, go ahead and make some pages and sub-pages. Preview your theme and it should work flawlessly. Let me know if you have any questions. Good luck!