How to route between internal networks in Hyper-V

If you have a Hyper-V lab environment and want to make it a little more like a corporate network then you might want to set up multiple networks and routing between them. But how would you accomplish that? There are different ways to solve it as a Vyatta router (or any other small Linux firewall) or perhaps a Forefront TMG. The way that I chose and that's very simple, you can read about on the following page.

http://www.infotechguyz.com/server2008/hypervrouting.html