This tool is very effective for stubborn screw removal. I found it to be faster and easier then traditional extraction techniques. It really accelerated my recent project.
http://www.sears.com/shc/s/p_10153_12605_66630679000P?vName=Gifts&cName=Tools&sName=All&psid=FROOGLE01&sid=IDx20070921x00003a&aff=Y&origin=prod
http://www.sears.com/shc/s/p_10153_12605_66630679000P?vName=Gifts&cName=Tools&sName=All&psid=FROOGLE01&sid=IDx20070921x00003a&aff=Y&origin=prod