Jim Cser has updated his wonderfully simple and easy to use (and free) ArcMap to KML tool.
`Fixes in 3.2.0
Removed the extra commas between line segments. KMLs now have compatibility with Google Maps.`
As always it is so simple to use. Just add the toolbar to your ArcMap session. Get your data layers set up the way you want.
And enjoy your KML inside Google Earth…