uBrowser is the 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.
Full documentation and various examples are available at: http://www.ubercart.org/docs/ubrowser
This module will not be updated to Drupal 6. It is no longer a requirement for Ubercart, and the code requires some special maintenance that leads me to believe there's "surely a better way". If someone is interested, they can contact rszrama to take over for Drupal 6 and beyond.
Module development sponsored by the Ubercart project.