remm

This plugin provide widget that display a list with categories and posts in your sidebar. 
Widget can save the opened categories, and use cache.

Wp Ajax Tree

This plugin provide a widget that display a category and pages tree on your sidebar, using ajax to collapse categories.

sekishi

Enable the jQuery treeview on the page of wordpress. 
It is easily editable on the TinyMCE.
Automatically selects the enclosing shortcodes.(version 0.1.4 or later) 
This mode is the same as the Easy Block Selector plugin.
Treeview On Contents Plugin Overview. 
http://lab.planetleaf.com/development/wordpress/treeview-on-contents-plugin.html
This plugin used jQuery Treeview Plugin. 
jQuery Treeview plugin http://bassistance.de/jquery-plugins/jquery-plugin-treeview/
A setup of JQuery Treeview Plugin is possible as the option of a shortcode [tvoncmeta].

Treeview On Contents

Enable editing of the treeview on TinyMCE.

Wp Ajax Tree vs Treeview On Contents