SME Server is an open-source server distribution providing many services, including networking, routing, file sharing, email and much more, in one easy-to-administer Web panel.
Written by Max Hetrick
If you're looking for a free, simple-to-set-up, ready-made Linux server, SME Server should fill your need. The current version, 7.5.1, is based on CentOS 4.8, but the next release, currently in beta, will utilize CentOS 5.5 as its base. For those unfamiliar with CentOS, it's a free re-branded version of Red Hat, so you should feel comfortable knowing it's built on a well-known enterprise platform.