I’d like to announce the release of my Treeview plugin for jQuery, which is based on the work of Myles Angell. It allows you to take nested unordered lists and convert them into a collapsable and expandable tree. It provides options to animate toggling, display the tree collapsed at first, select certain branches to start open or closed, and to create a tree controller to collapse, expand or toggle all branches at once.
Documentation, a demo, downloads can all be found on the Treeview plugin page.
Have fun using the treeview, your feedback is of course appreciated.