Something like this is probably what you're looking for:
Code:
BindAddress 192.168.1.100
Listen 192.168.1.100:80
<VirtualHost 192.168.1.100>
ServerName blah.com
ServerAlias blah
DocumentRoot /var/www/docroot
HostNameLookups off
TransferLog logs/access.blah
ErrorLog logs/errors.blah
</VirtualHost>
<VirtualHost 192.168.1.100>
ServerName blah1.com
ServerAlias blah1
DocumentRoot /var/www/docroot1
HostNameLookups off
TransferLog logs/access.blah1
ErrorLog logs/errors.blah1
</VirtualHost>
So, whenever someone hits "blah.com" they will see whatever pages you setup in /var/www/docroot, while someone else that hits "blah1.com" will see whatever is in /var/www/docroot1. I don't use ip based virtual host, I use name based virtual host. To me, that's easier but it's really up to you.
How are people hitting your site now? Just people on your internal network or outside as well? If people from the outside are hitting your site, then you must be forwarding httpd requests from your router to your linux box.
-twantrd