php server variables list

Open source script to display a tree-view site map?
I'm looking for a good open-source or other free script to display an expandable/collapsable "tree" or "explorer" list of web pages on a site, probably in Javascript. It'd also be nice if it's generated on the server-side by PHP or some other scripting language, using data files or array-variables to store the source data, making updates & maintenance reasonable. Thanks for any help!
This is one of the best. It has received numerous awards from PlanetSourceCode and it's OpenSource. Here's a link to the Author's site:
http://www.superchiefsoftware.com/Products.aspx
[phpbay]php server variables list, 30, "11211"[/phpbay]
[phpzon]php server variables list, 5, Electronics[/phpzon]
Extending C: "Variable Variables" like PHP $$var