jquery-accordion
This plugin creates an accordion menu. It works with nested lists, definition lists, or just nested divs. Options are available to specify the structure, if necessary, the active element (to display at first) and to customize animations. The navigation-option automatically activates a part of the accordion based on the current location (URL) of the page.
Current version: 1.6 (last standalone release, now part of jQuery UI)
Compressed filesize: 3829 bytes
License: MIT/GPL
demo