I've been playing a lot with virtual machines recently, and I intend to write about my experiences and why I wanted to do this another time. For now, here is a small practical tip. All of the main virtual machine packages (VirtualPC, VMWare and VirtualBox) provide mouse pointer integration, which means when the mouse leaves the window of the guest system, it continues seamlessly into the host system. Sometimes this is not what you want, e.g. if the guest system is running software that uses the fact that the mouse has reached the edge of the screen. Some 3D software, including games, makes use of this fact to pan the image. For VirtualPC and VirtualBox, it's easy to turn this off. For VMWare, it is much harder. Some people say that you can add the line vmmouse.present="FALSE" to the configuration (.vmx) file, or to not install the VMWare mouse driver. Neither worked when I tried. What does work is to disable the VMTools service if you have it running. On Windows 2000, you can do this by going to services in the administrative tools (or running services.msc) and stopping or disabling the service. Then the mouse pointer integration will stop as well, at the cost of losing some things like the shared folder functionality.
I know this will be all mumbo-jumbo to most people, but I couldn't find it said explicitly anywhere else, and perhaps it'll help someone out there on the web. Leave me a comment if it does.