vi /etc/yum.repos.d/webmin.repo

[Webmin]
name=Webmin Distribution Neutral
#baseurl=http://download.webmin.com/download/yum
mirrorlist=http://download.webmin.com/download/yum/mirrorlist
enabled=1

wget http://www.webmin.com/jcameron-key.asc
rpm –import jcameron-key.asc

yum install SSLeay perl-Net-SSLeay OpenSSL perl-Crypt-SSLeay
yum install webmin

vi /etc/webmin/miniserv.conf
ssl=1
service webmin start

If you didn’t enable SSL, you can get:
SSL Error On First Access of Webmin on New Install – (Error code: ssl_error_rx_record_too_long)