The project page for uBrowser at Drupal.org is http://drupal.org/project/ubrowser.
uBrowser is a new way to browse taxonomy for Drupal 5.x. It creates an easy to use interface for browsing vocabularies (categories) like you would browse a directory tree. Each term in the vocabulary is like a file folder, and clicking on it in the category select box will display all the nodes that have been classified with that term in the node select box. The look may be changed in the CSS, but other display options such as search forms, action buttons, and display names may be specified when the uBrowser is built for display.