If you want to setup a script using passive stereo you'll need to issue viz.STEREO within the viz.go statement and then span the display over the two projectors. Here is an article that explains how to set that up using an nVidia card under Windows XP.
http://kb.worldviz.com/articles/916
Once your display is setup properly you can try the World demos that come with Vizard. Some of them have a prompt that will allow you to enable stereo.