Webmin

Webmin is my personal favorite of the free control panels. I have used it for many years on servers I have set up at home to test and play with. It is easy to set up and has a great list of feature (or modules) including Apache, BIND, BSD Firewall, bandwidth monitoring, cron job manager, and many more. Beyond the standard modules included, you can download addition third party modules and develop your own if needed.

Currently there is support for many types of Unix (best option: FreeBSD), Linux (best option: Redhat), and Solaris systems. Webmin needs to be configured for each specific flavor of *nix because of file locations, but despite this restriction, there are currently 82 different operating systems supported.

Webmin uses a BSD-like license allowing for commercial and non-commercial use. "All recent versions of Webmin are under a BSD-like licence, meaning that it may be freely distributed and modified for commercial and non-commercial use" (Webmin).

Web-cp

web-cp offers security, flexibility, automation, and management tools to help you manage your servers. Some notable features include system monitoring, statistics, domain configuration, database management, email settings, file manager, and many more. There is a list of supported applications on the web-cp website including sendmail, Apache, Bind, and MySQL.

Running on *nix systems, there are currently 12 different operating systems that web-cp can run on. Multiple versions of Redhat, FedoraCore, FreeBSD, and CentOS are a few of the available options.

The license for this control panel is licensed as Open Source software under the GPL license. This license means that "anyone, anywhere can continue working on the code" (web-cp).

SysCP

SysCP includes management of mail, FTP, web space, CGI, custom error pages, statistics, DNS, and more. Within these categories of supported features, you can control popular applications such as Apache, Bind, Courier, and Proftpd.You can get full feature and supported applications lists from their website. As well as these standard application controls built into SysCP, you can download third party modules to control and manage other aspects of your server as well. Some of the third party modules include management for applications like SpamAssassin, Fetchmail, and a backup module.

You can use SysCP on five major *nix distibutions, Debian, Ubuntu, Gentoo, OpenSuSE, and FreeBSD. These are limited to specific versions so be sure to check what you are using versus what is supported.

SysCP is licensed as open source using the GPL. "The SysCP project was founded, to develop a free server management tool in terms of the Open Source Definition and distribute it freely under the terms of the GPL" (SysCP).

GNUPanel

GNUPanel is written in PHP5 and is intended to run on a Debian Linux system. The main features include domain management, FTP management, database administration, mail management, and much more. You can control popular applications like Apache, PHP, MySQL, Proftpd, and others. There are also some web applications available for auto installation (WordPress, Joomla, phpBB, and osCommerce).

Although you can currently only run this on Debian, there are other operating systems installations planned. Current development is focusing on language translations of the application.

The license is open source, using GPL. The website stats that "GNUPanel is a completely free (GPL)" (GNUPanel).

ISPConfig

ISPConfig offers management of services like httpd servers, FTP servers, DNS servers, mail servers, database systems, and much more. You can get a full list of features at their website. You can manage popular applications like Apache, MySQL, Proftpd, Bind, and sendmail through the control panel as well. An additional feature of ISPConfig that can be a great deal of help is the four page listing of how-to's at HowtoForge.

There are eight major Linux distributions supported including Mandrake, Fedora Core. Suse, Debian, and Ubuntu. A number of different versions are supported for each of the eight supported operating systems.

ISPConfig uses a BSD license, which allows for redistribution and copying as well as changing the source as long as the original copyright information is retained.

Shared hosts offer great features and prices for both new webmasters just starting out and seasoned webmasters. The best feature is typically the price. A lot of shared hosts can offer basic plans for under $10 a month. The extensive bundle of features you get for that cost is not always the best way to go however. There are often terms and conditions (which are skipped over all too often) that can make the best price and feature combination not worth a tenth of what they are charging. Here is a list of 5 things, in no particular order, to verify before deciding on a shared hosting plan.

1. 99.9% Up Time - Verify that the plan includes 99.9% up time. This is in my opinion the most important one because if the host isn't committed to keeping the connections and servers running at all times, it doesn't matter what features or deal you get, your website will be unreachable.
2. Unlimited = Unlimited - Verify that if your host advertises an unlimited amount of anything, you will indeed get unlimited amounts of it. Some hosts will offer unlimited bandwidth for instance, but throttle you if you start consuming too much. Another downfall with unlimited (bandwidth in particular) is the impact other users can have on the system. If the host doesn't have a limit in place, one user could consume a large percentage of resources, which will in turn decrease the performance of your website.
3. Exceeding the Limit - Verify that the host doesn't suspend an account that goes beyond its allocated limits per month, whether it be bandwidth or another limited feature. This may not be a bad thing for those webmasters who are not relying on the website for anything, or those who are not looking to have a regular following (I don't know very many of those kinds of webmasters), but it is very bad for webmasters that can't have down time. If at all possible, try to make sure that your account isn't suspended for going over; have them charge you accordingly. If you aren't comfortable with this route, make sure that you keep a close eye on your limits and make the necessary adjustments to ensure you don't exceed your limits.
4. Established Support Record - Verify that the host has an established and verified customer support record. You will inevitably need to talk to support when your site goes down, because it will go down, and I have dealt with hosts that take around 4-6 hours to get back to you. Make sure that you can talk to someone within minutes if your site is experiencing problems. You aren't able to do much to help your site when using a shared host, so you will rely mostly on the support they offer. THIS IS KEY!
5. Speed of Upgrades - Verify that your host will upgrade to the new releases of features such as PHP, MySQL, cPanel, etc. as soon as possible after the stable releases become available. I have heard many cases, and been a part of cases, where you buy the most recent version as part of your hosting package and the releases don't get updated/upgraded after that. The new machines that are set up get the new releases, but the machine you are on might not get them for months or even years after the release.

Have you dealt with something that might not be a typical item to watch out for? Let us know in the comments if you have any tips to keep us aware.