I am working on a solution for a friend of mine who has a small business.  He has an application that runs on Windows 2000 Server (which we plan on upgrading to Windows 2003).  I want to put a better Firewall in place (Smoothwall), and I would like to run this on the Same machine that Terminal Services is running on.

So, I could use VMWare – But I would prefer something cheaper, largely due to my friends budget.  I saw a recent article where thanks to Intel, XEN will support Windows in 2005, but that doesn’t help me now.  In the meantime, what other alternatives exist to running Windows / Linux on the same box, to give me a working configuration similar to what I describe above ?