I have managed to run more than 1 apache site site before using either a IP-based hosts or Name-based virtual hosts http://httpd.apache.org/docs/1.3/vhosts/name-based.html
IP-based hosts is a simpler one for you do not need to configure DNS as opposed to Name-based where you need DNS to resolve the name of the virtual server.
With IP-based, you need to create a virtual network interface under eth0. You can name it eth0:1
Unfortunately, I only know how to create a virtual interface using webmin. So I can help you if you are familiar with webmin or you are willing to try webmin. Webmin is easy to learn anyway.
The only disadvantage of IP-based hosts that I have noticed is that you can only host one site at a time over the internet should you require to make your sites available on the internet. On your LAN its ok though because you can simply browse to the correct IP address.
Having that in mind, I would say name based hosts is much better, it uses one IP address for all apache virtual hosts. Its also easy to setup using webmin and virtualmin. Virtualmin will automatically handle your DNS settings for you.
I'm not sure if there are ways of overcoming that limitation in IP-based hosts, I'm just speaking from my knowledge and experience.
Let me know when you are ready.