Some recent changes to Shape2Earth for MapWindow has made it even easier to convert shapefiles to KML for viewing in Google Earth. In the past, it was necessary to download MapWindow, and then install Shape2Earth separately as a plugin. The new install package bundles MapWindow Version 4.7.5 with Shape2Earth in a single installation.
Shape2Earth is a very powerful and easy to use system for creating thematic maps for Google Earth using open source GIS.
A new video on YouTube shows you just how easy it is.