This plugin turns an ordinary HTML select control into elegant drop down list of checkboxes, stylable with ThemeRoller.
Based off of Cory S.N. LaViska's implementation, A Beautiful Site (http://www.abeautifulsite.net) 2009.

Demos and documentation @ http://www.erichynds.com/jquery/jquery-multiselect-plugin-with-themeroller-support/