Install Webmin on Ubuntu 12.04
Note: This post assumes a web server is already installed. Note: This post assumes you have administrative rights on the system. Like always you should update and upgrade the installation.
sudo apt-get update
sudo apt-get upgrade
Download Webmin
Visit webmin.com/download.html and download the .deb version of Webmin.
cd /tmp
wget http://prdownloads.sourceforge.net/webadmin/webmin\_1.590\_all.deb
Installation
Now that we have the package we can install it.
sudo dpkg -i webmin_1.590_all.deb
Actually dpkg will not be able to install Webmin because of some missing dependencies. This is why we need an extra step which will fetch the missing dependencies for us.
sudo apt-get install -f
Now you can log-in to the newly installed Webmin interface by going to the following address. Just add the IP address of the server.
https://server\_ip\_address:10000
Remember the log-in credentials for Webmin are the username and password you used to log in to the server. 
Conclusion and Links
Comments and corrections are always appreciated. Webmin Home Page http://www.webmin.com