Virtual PC simulator can simulate up to 9 PC's. It is not the traditional PC , it just a program for Linux & Windows and only few network commands can we used it it. But VPCS can give you a big hand when you study the Cisco devices in the Dynamips. VPCS can replace the routers or VMware boxes which are used as PCs in the Dynamips network.
Download lastest version VPCS
It is a best program for GNS3. We can use IPV4 and IPV6 in this program along with Cisco Routers.