Using VMWare workstation with a HOST only network, setup Windows Server 2008 with 2 NICS and ICS. One NIC is connected to the HOST only network with the other connected via Bridged network connection to the lab network allowing it to connect to the Internet. This setup uses 172.16.0.0 network on the HOST only network. This will allow a workstation with 172.16.0.100 address to route out to the Internet via your Windows 2008 Server with an IP of 172.16.0.10.
The rest is here:
Internet Connection Sharing – Windows 2008 Server