pfSense - virtual firewall and router VMware appliance

pfSense is a free, open source customized distribution of FreeBSD tailored for use as a firewall and router. In addition to being a powerful, flexible firewalling and routing platform, it includes a long list of related features and a package system allowing further expandability without adding bloat and potential security vulnerabilities to the base distribution. pfSense is a popular project with more than 1 million downloads since its inception, and proven in countless installations ranging from small home networks protecting a PC and an Xbox to large corporations, universities and other organizations protecting thousands of network devices.

A VMware Appliance is available here: http://doc.pfsense.org/index.php/VMwareAppliance
I’ve also created a vSphere compatible OVA file which is available here: http://www.screencast.com/users/esloof/folders/pfSense