zackdesign

Note: This plugin requires PHP 5
Warning: This plugin requires knowledge of CSS to use adequately in widgets
Features at a glance:
<ul>
<li>Widgetised to make it really easy to add multiple dropdowns anywhere on the page you have sidebars</li>
<li>Ability to create the menu wherever you want with PHP Classes</li>
<li>Leverages the new WordPress 2.8 widget settings to allow quick and easy multiple widget instances</li>
</ul>
Theming options:
<ul>
<li>Multi-level dropdown (CSS included)</li>
<li>Multi-level left/right flyouts (CSS included)</li>
<li>Support for Superfish Javascript (CSS included)</li>
<li>Works with other CSS (within reason)</li>
</ul>
If you want me to modify the CSS for you simply <a href="http://www.zackdesign.biz" title="Zack Design" rel="nofollow ugc">contact me</a> and I will do it easily and quickly for you for a moderate sum.
It uses <a href="http://www.cssplay.co.uk/menus/final_drop.html" title="Stu Nicholl" rel="nofollow ugc">Stu Nicholl’s final drop-down code</a> which is a complete CSS solution – no Javascript required!!
You can look on <a href="http://www.cssplay.co.uk/menus/" title="Stu Nicholl's Menus" rel="nofollow ugc">Stu’s site for other drop-down code</a> as I got the flyout left and right code from there. Don’t forget to donate if you’re using his styles.
Most of his CSS should work just fine with the menu. I’ve made it so that the plugin automatically finds menu.css in the plugin’s folder and loads it in your WordPress site so you can instantly see how it will look. If you want to create your own CSS simply create menu.css in your theme’s root directory and the plugin will load that automatically for you.
Please note that if you’re upgrading you will need to change your theme files to suit the new approach. See Installation for further information.

WordPress CSS Drop-down Menu

Use Wordpress' nav menu system to create left/right widget flyouts, with support for Superfish

Philipp Speck

With this plugin you can edit sidebar contents like posts in the admin area and assign them from a dropdown menu to any post or page. It supports flexible dropping via widget for independent theme association.
It’s a matter of fact that people don’t want to code when they just want to change their contents. To keep a website interesting for visitors you can change the sidebar contents in context to the main content. Before you could realize it with different sidebar templates or conditional tags. 
Now you can do all these great things inside the admin area without any coding. 
Any anyway: Since we organize informations in databases all contents should be stored there as well.
From a dropdown menu you can easily choose all sidebars you have created.
<h4>Features</h4>
<ul>
<li>Own <code>meta box</code> on post/page edit pages</li>
<li>Own menu item in admin menu</li>
<li>Registrates own <code>post type</code> for sidebars</li>
<li>Full editable sidebars like posts</li>
<li>Assign sidebars from dropdown menu</li>
<li>Flexible widget support</li>
<li>No coding needed</li>
<li>Oldest sidebar as default post</li>
<li>Loads sidebar from parent page if not assigned for children</li>
<li>Localization in English and German</li>
</ul>
<h4>Related Links</h4>
<ul>
<li><a href="http://www.typomedia.org/wordpress/plugins/wordpress-custom-sidebar/" title="Homepage of WordPress Custom Sidebar" rel="nofollow ugc">Homepage</a></li>
<li><a href="https://wordpress.org/extend/plugins/wordpress-custom-sidebar/changelog/" title="Changelog for WordPress Custom Sidebar" rel="ugc">Changelog</a></li>
<li><a href="https://wordpress.org/extend/plugins/wordpress-custom-sidebar/faq/" title="FAQ for WordPress Custom Sidebar" rel="ugc">Questions</a></li>
</ul>
Note: 
First drop the widget in the sidebar of your choice. Now uses oldest sidebar as default sidebar. Before installing or upgrading new plugins, please backup your database first! After upgrading to ‘WordPress Custom Sidebar 2.0’ you have to assign the widget again.

WordPress Custom Sidebar

With this plugin you can handle sidebar contents like posts and assign them from a dropdown menu.

WordPress CSS Drop-down Menu vs WordPress Custom Sidebar