Jim Cser writes:

I just wanted to announce a long-overdue update to KML Home Companion, my ArcGIS extension. Version 3.2 removes the extraneous commas, making the KML files compatable with Google Maps. Downloadable from ESRI ArcScripts, or from the Google KML Dev Support forum.

KML Home companion is a free ArcGIS extentsion that converts ArcMap layers into KML.