Perseusguard

License
Released under GNU/GPL V.2.0 license
Introduction
PerseusGuard is a meta-distribution based on Ubuntu Linux, that acts as a centralized Proxy/Content Filter/'Anti virus in LAN environments for protecting PC clients.
PerseusGuard is available in three different kinds of download:
*Iso format. A standard ISO image – derived from Ubuntu server LTS 10.04 – for direct installation on PC (real or virtual)
*From Scratch version (.tgz package) –The scripts contained into the package will “generate” PerseusGuard starting from Ubuntu Server
*“Virtual Appliance” for Vbox OSE (Not ready yet! It will be available soon! Check official web-site for news)
The technologies involved are the best from Open Source: Squid, SquidGuard, Havp,ClamAV and Ubuntu 'Linux. PerseusGuard also provides a dedicated web interface for an easy-configuration-management of all the services above ( written in Object-Oriented PHP ). 
Full description of the project, manuals, download @ official page