Gufw

You probably know that ubuntu 8.04 includes an inbuilt firewall called ufw or the uncomplicated firewall.But ufw is command line driven and there is no GUI for it by default.But now you can get yourself Gufw,a linux based firewall based on ufw.It is more appropriately a GUI for ufw.So you can create host based firewalls without typing in commands in the terminal.This is a great piece of application for beginnners.Open Gufw from the Internet menu and enable firewall by simply tick marking a radio button.Create IPv4 and IPv6 host based firewalls and even hide IP.The help file included in this package is great way to learn more about setting up new rules in the firewall.Once configured Gufw rests in the notification area and you can enable/disable it right from there.
Refer to screenshots for more.
Download the Gufw debian package.
Watch the video here.