About
The NestedSortables are a set of two jQuery plugins, build on top of the Interface for jQuery, that allows you to sort and nest elements using drag and drop.
NestedSortable
The first, low level one is the NestedSortable. It can be set up very similarly to the Sortable plugin in Interface. You can check its documentation, with examples, here. A working demo can be seen in this page.
NestedSortable Widget
The second, high level one is a widget or component. It is called NestedSortable Widget (I have a great imagination). You can check its documentation, with examples, here. A working demo can be seen in this page.
Additional Information
These plugins were developed for WordPress as a Google Summer of Code project, in 2007. They were designed to allow the user to easily sort their blog pages.
More information about the development of this plugin can be seen in my blog.
Licenses
Dual Licensed under MIT and GPL, just like jQuery.