The basic screen saver worked before, but searching for an alternative time zone would crash System Preferences. That is now fixed.
The screen saver also shows a thumbnail image when in Mountain Lion and is code-signed with my developer ID for compatibility with Mountain Lion’s Gatekeeper.
The current version is compatible with 10.8 and 10.7. It may work in 10.6 but I cannot be sure. If anyone tries it, please let me know.