This Add-on hides the original keywords viewlet and adds a new one that is based on Tag-Handler (https://github.com/ioncache/Tag-Handler). It allows you to change the keywords/tags via ajax requests.
Just add collective.ajaxkeywords to yout eggs and zcml section in your buildout
collective.ajaxkeywords is copyright 2011 by Dominik Ruf, and is licensed under the GPL. See docs/LICENSE.txt for details.