jquery-option-tree is a jquery plugin help you presentation & maintain a tree structure very easy with json data.
you only need to build a nested json string on server-side.this is very easily with ruby ,python dynamic language.
i use this plugin in a tree category situation,i think this also is a common way to use this plugin,
the author kotowicz is a very nice guy,i submit a issue and he fixed it the same day immediately.
i introduce here to help more people to know it.
example
http://kotowicz.net/jquery-option-tree/demo/demo.html
souce
http://code.google.com/p/jquery-option-tree/