<div id="leftcol">
<ul>
<li id="pages-3" class="widget widget_pages">
<h2 class="widgettitle">Pages</h2>
<ul id="accordion-menu-pages-3-level0" class="accordion-menu">
<li class="page_item page-item-3 current_page_item"><a title="jQuery Accordion Menu for WordPress" href="http://bruzed.com/accordion-menu">jQuery Accordion Menu for WordPress</a></li>
<li class="page_item page-item-5"><a title="About the plugin" href="http://bruzed.com/accordion-menu/about-the-plugin/">About the plugin</a>
<ul id="accordion-menu-pages-3-level1" class="accordion-menu" style="display: block;">
<li class="page_item page-item-7"><a title="Description" href="http://bruzed.com/accordion-menu/about-the-plugin/description/">Description</a></li>
<li class="page_item page-item-9"><a title="Installation" href="http://bruzed.com/accordion-menu/about-the-plugin/installation/">Installation</a></li>
<li class="page_item page-item-11"><a title="FAQ" href="http://bruzed.com/accordion-menu/about-the-plugin/faq/">FAQ</a></li>
<li class="page_item page-item-13"><a title="Changelog" href="http://bruzed.com/accordion-menu/about-the-plugin/changelog/">Changelog</a></li>
</ul>
</li>
<li class="page_item page-item-18"><a title="About me" href="http://bruzed.com/accordion-menu/about-me/">About me</a>
<ul id="accordion-menu-pages-3-level1" class="accordion-menu" style="display: none;">
<li class="page_item page-item-20"><a title="Blog" href="http://www.bruzed.com" target="_blank">Blog</a></li>
<li class="page_item page-item-22"><a title="Portfolio" href="http://portfolio.bruzed.com" target="_blank">Portfolio</a></li>
</ul>
</li>
<li class="page_item page-item-25"><a class="smcf-link" title="Contact" href="http://bruzed.com/accordion-menu/contact/">Contact</a></li>
<li class="page_item page-item-75"><a title="Buy Bruce a coffee" href="http://bruzed.com/accordion-menu/buy-bruce-a-coffee/">Buy Bruce a coffee</a></li>
</ul>
</li>
</ul>
</div>

Here’s the source from functions.php:

<?php
/**
* @package WordPress
* @subpackage Default_Theme
*/

automatic_feed_links();

if ( function_exists('register_sidebar') ) {
register_sidebar(array(
'before_widget' => '<li id="%1$s" class="widget %2$s">',
'after_widget' => '</li>',
'before_title' => '<h2 class="widgettitle">',
'after_title' => '</h2>',
));

}

?>

How to use the accordion menu for subpages on the sidebar?

Here’s an example to apply the accordion menu to subpages on the sidebar. This uses the sidebar template from the default theme.

<?php
/**
 * @package WordPress
 * @subpackage Default_Theme
 */
?>
	<div id="sidebar" role="complementary">

		<ul>

			<!--applying the accordion menu to subpages-->
			<li id="subpages" class="widget widget_pages">
				<?php
				if($post->post_parent)
					$children = wp_list_pages("title_li=&child_of=".$post->post_parent."&echo=0"); else
					$children = wp_list_pages("title_li=&child_of=".$post->ID."&echo=0");
				if ($children) { ?>
					<ul>
						<?php echo $children; ?>
					</ul>
				<?php } ?>
			</li>

			<?php 	/* Widgetized sidebar, if you have the plugin installed. */
					if ( !function_exists('dynamic_sidebar') || !dynamic_sidebar() ) : ?>
			<li>
				<?php get_search_form(); ?>
			</li>

			<!-- Author information is disabled per default. Uncomment and fill in your details if you want to use it.
			<li><h2>Author</h2>
			<p>A little something about you, the author. Nothing lengthy, just an overview.</p>
			</li>
			-->

			<?php if ( is_404() || is_category() || is_day() || is_month() ||
						is_year() || is_search() || is_paged() ) {
			?> <li>

			<?php /* If this is a 404 page */ if (is_404()) { ?>
			<?php /* If this is a category archive */ } elseif (is_category()) { ?>
			<p>You are currently browsing the archives for the <?php single_cat_title(''); ?> category.</p>

			<?php /* If this is a daily archive */ } elseif (is_day()) { ?>
			<p>You are currently browsing the <a href="<?php bloginfo('url'); ?>/"><?php bloginfo('name'); ?></a> blog archives
			for the day <?php the_time('l, F jS, Y'); ?>.</p>

			<?php /* If this is a monthly archive */ } elseif (is_month()) { ?>
			<p>You are currently browsing the <a href="<?php bloginfo('url'); ?>/"><?php bloginfo('name'); ?></a> blog archives
			for <?php the_time('F, Y'); ?>.</p>

			<?php /* If this is a yearly archive */ } elseif (is_year()) { ?>
			<p>You are currently browsing the <a href="<?php bloginfo('url'); ?>/"><?php bloginfo('name'); ?></a> blog archives
			for the year <?php the_time('Y'); ?>.</p>

			<?php /* If this is a search result */ } elseif (is_search()) { ?>
			<p>You have searched the <a href="<?php bloginfo('url'); ?>/"><?php bloginfo('name'); ?></a> blog archives
			for <strong>'<?php the_search_query(); ?>'</strong>. If you are unable to find anything in these search results, you can try one of these links.</p>

			<?php /* If this set is paginated */ } elseif (isset($_GET['paged']) && !empty($_GET['paged'])) { ?>
			<p>You are currently browsing the <a href="<?php bloginfo('url'); ?>/"><?php bloginfo('name'); ?></a> blog archives.</p>

			<?php } ?>

			</li>
		<?php }?>
		</ul>
		<ul role="navigation">
			<?php wp_list_pages('title_li=<h2>Pages</h2>' ); ?>

			<li><h2>Archives</h2>
				<ul>
				<?php wp_get_archives('type=monthly'); ?>
				</ul>
			</li>

			<?php wp_list_categories('show_count=1&title_li=<h2>Categories</h2>'); ?>
		</ul>
		<ul>
			<?php /* If this is the frontpage */ if ( is_home() || is_page() ) { ?>
				<?php wp_list_bookmarks(); ?>

				<li><h2>Meta</h2>
				<ul>
					<?php wp_register(); ?>
					<li><?php wp_loginout(); ?></li>
					<li><a href="http://validator.w3.org/check/referer" title="This page validates as XHTML 1.0 Transitional">Valid <abbr title="eXtensible HyperText Markup Language">XHTML</abbr></a></li>
					<li><a href="http://gmpg.org/xfn/"><abbr title="XHTML Friends Network">XFN</abbr></a></li>
					<li><a href="http://wordpress.org/" title="Powered by WordPress, state-of-the-art semantic personal publishing platform.">WordPress</a></li>
					<?php wp_meta(); ?>
				</ul>
				</li>
			<?php } ?>

			<?php endif; ?>
		</ul>
	</div>