KML (Keyhole Markup Language) is an XML-based language for managing three-dimensional geospatial data in Google Earth. KML files are often distributed as KMZ, zipped KML files. The KML file specifies a feature (a placemark, image, or polygon) for Google Earth, by describing the longitude, latitude, tilt and other information.
Now you can use KMZ files in Google Maps, not only in Google Earth. If you know the address of a KMZ file, paste it into Google Maps search box.
Here are some nice places to see in Google Maps:
The seven wonders of the world
Earthquakes from the last week
World Cup 2006 stadiums
Eiffel Tower
World's top 500 hotels
Related:
Google Earth 4 just launched