vZome is a desktop app designed primarily for building virtual Zome models. It goes much further than this, however, supporting models and geometries not possible with Zome.
If you are on Windows or Linux, you can download and launch a trial version of vZome using Java Web Start... no need to install anything! If you are on Mac OS X, you can download, install, and launch a packaged trial version of vZome. The trial version lets you use all the features, but does not let you save model files. To obtain a free, fully capable personalized license for vZome, please send a note to me ("scott") at "vorthmann.org", and I'll reply within a day or less, typically.
vZome will not run without Java. If the Java Web Start link above does not work for you, you may need to install the Java Runtime Environment 1.4 or newer.