well simply i would go out and buy or geta cracked version of VM ware 3.0 or higher it aloows you to setup virtual machines on one system and allows them to bridge network witch means setup up a network with x machines on one system for more advice i would go to the web site
and do some reserach coz far as i know its the best program out there and at the same time you can learn about networks and there problems i use this software daily for free and all other microsoft products.

so enjoy

Regards Agent Nomad