if you want know know how to uninstall and remove webmin after you have installed it with rmp, you can do this:

Just run the command

COMMAND:
/etc/webmin/uninstall.sh



If you have installed the RPM version of Webmin like i have, you can use

rpm -e webmin


if you need more information on how to compeletely remove it go to:
http://www.webmin.com/faq.html