Drupal Module Jquery Multiselect
This drupal module includes the jquery ui multiselect plugin. http://quasipartikel.at/multiselect/
It integrates with the http://drupal.org/project/jq module which aggregates jquery plugins for easy administration.
Drupal.org project page : http://drupal.org/project/jquery_multiselect
Drupalmodules.com : http://drupalmodules.com/module/jquerymultiselect