Before you begin:

Ideally you should install this on a clean system (ie: one that has the bare minimum to get a *nix system running, but you shouldn't have any problems if it isn't as I have installed this on a dirty machine many times without problems.

You will need access to a shell via SSH or locally. You will also need Perl installed (usually default for *nix) and also Wget for the download.

Right, off we go!

Bring up a shell and navigate to /usr/local (you'll probably be in roots home directory when first logged in)

type the following command:
wget http://prdownloads.sourceforge.net/webadmin/webmin-1.310.tar.gz

Once the download has completed you need to unzip by using:
gunzip webmin-1.310.tar.gz

and then:
tar xvf webmin-1.310.tar

You should then be left with a directory called webmin-1.310. Find out by doing a simple "dir" command.

Lets rename that:

mv -i webmin-1.310 webmin

Now move into the webmin directory:
cd webmin

Now the good stuff, type the following:
./setup.sh

You should be greeted by the following screen and several questions. You can leave most of the questions on default by hitting return except of course for the username and password!!!

[root@frodo webmin]# ./setup.sh


******************************************************************
* Welcome to the Webmin setup script, version 1.130 *
******************************************************************
Webmin is a web-based interface that allows Unix-like operating
systems and common Unix services to be easily administered.

Installing Webmin in /usr/local/webmin ...

******************************************************************
Webmin uses separate directories for configuration files and log
files. Unless you want to run multiple versions of Webmin at the
same time you can just accept the defaults.

Config file directory [/etc/webmin]: /usr/local/etc/webmin
Log file directory [/var/webmin]: /usr/local/var/webmin

******************************************************************
Webmin is written entirely in Perl. Please enter the full path to
the Perl 5 interpreter on your system.

Full path to perl (default /usr/bin/perl):

Testing Perl ...
Perl seems to be installed ok

******************************************************************
Operating system name: Centos
Operating system version: 4.0

******************************************************************
Webmin uses its own password protected web server to provide
access to the administration programs. The setup script needs to
know :
- What port to run the web server on. There must not be another
web server already using this port.
- The login name required to access the web server.
- The password required to access the web server.
- If the webserver should use SSL (if your system supports it).
- Whether to start webmin at boot time.

Web server port (default 10000):
Login name (default admin): root
Login password:
Password again:
The Perl SSLeay library is not installed. SSL not available.
Start Webmin at boot time (y/n): n
******************************************************************
Creating web server config files..
..done

Creating access control file..
..done

Inserting path to perl into scripts..
..done

Creating start and stop scripts..
..done

Copying config files..
..done

Creating uninstall script /usr/local/etc/webmin/uninstall.sh ..
..done

Changing ownership and permissions ..
..done

Running postinstall scripts ..
..done

Attempting to start Webmin mini web server..
Starting Webmin server in /usr/local/webmin
..done

******************************************************************
Webmin has been installed and started successfully. Use your web
browser to go to

http://frodo:10000/

and login with the name and password you entered previously.

[root@frodo webmin]#


You should now be able to goto http://yourdomain.net:10000 and login with your username and password given above.

As a failsafe, webmin creates an uninstall script. If you need to uninstall webmin, goto the same directory you used to setup and issue the following:
./uninstall.sh

Happy servering!