From the developer:
"BrickHouse is designed to make using the network firewall built in to Mac OS X quick and easy. By using BrickHouse to enable your computer's firewall, you can help prevent unauthorized villains from gaining access to your computer via your Internet connection. BrickHouse also helps you use your firewall to guard against denial of service or resource-based Internet attacks. Network attacks will bounce off the firewall to prevent your computer from slowing down or crashing.
"BrickHouse provides a simple and easy interface for setting and activating your firewall's filters. It also includes a firewall monitor window to allow you to see how often each filter is used. Filter settings can be saved and switched quickly and imported and exported to and from disk. Settings can be created by knowledgeable users and administrators, and distributed to others to disable specific or recently discovered attack techniques."