Yes, you need a name server or an edited hosts file on every computer.
You will also need to set up virtual name based hosting in apache, if that's what you're using.
127.0.0.1 localhost
192.168.0.100 mybox
192.168.0.100 site.mybox
192.168.0.100 site2.mybox
If the IP of your computer (from now on known as mybox) is 192.168.0.100 you would have something like this in your hosts file:
Code:127.0.0.1 localhost 192.168.0.100 mybox 192.168.0.100 site.mybox 192.168.0.100 site2.mybox
It may be that you need to reboot for your computer to take the changes once you edit the hosts file.