Have you run several Virtual Hosts with the same IP address?
Yes, I run multiple Virtual Hosts on my development server and they all look like this:
NameVirtualHost *:80
<VirtualHost *:80> DocumentRoot /var/www/html/site1 ServerName site1.localhost other stuff .... </VirtualHost>
<VirtualHost *:80> DocumentRoot /var/www/html/site2 ServerName site2.localhost other stuff .... </VirtualHost>
<VirtualHost *:80> DocumentRoot /var/www/html/site3 ServerName site3.localhost other stuff .... </VirtualHost>
Have you got your ServerNames set up properly in /etc/hosts or DNS?