In order to use name-based virtual hosts in apache 2.x you will need to set up name resolution for each of your virtual hosts to an ip address (mult. hosts -> 1 ip).
I'm assuming, given your setup that you are not running your own DNS server. Therefore to do this, each system attempting to access your web server would need the appropriate entries in /etc/hosts or in C:\WINNT\System32\Drivers\etc\hosts on a windoze box.
From there, you can set up name based hosting as shown in apache's documentation: