Gallery 1.3.3 has now been ported to Drupal and released as a module. This integrates into the Drupal user permissions system, and offers simple user-management for creation/addition/admin of galleries and photos. You can bulk-upload photos using zip files, view slideshows (with nifty cross-fade transition effects in Internet Explorer) and take advantage of many of the other cool features of Gallery.
It's working with the current Drupal release (version 4.1.0), and you can grab it from the downloads page.
Nearly everything works, but there are certain minor limitations due to the way Drupal and Gallery are implemented. Please see the README for details and for more information.