It's an easy, two-step process to convert ArcGIS layers and shapefiles to KML with ExpertGPS Pro. View your ArcGIS points, polylines, and polygons over Google Earth's color imagery, and create KML files from your shapefiles to share with clients or to publish online.
The first step in converting ArcGIS data to KML is to Import ArcGIS Data, using Import on the File menu. ExpertGPS Pro automatically reprojects your ArcGIS layers from UTM, state plane coordinates, or any other projection into KML's native format (latitude and longitude in decimal degreees, in WGS84 datum).
To finish the ArcGIS-KML conversion, press F7, the View in Google Earth command, and ExpertGPS will convert your ArcGIS data to KML and automatically launch Google Earth to view your KML data. You can also click Export on the File menu to convert your shapefiles to KML.
You might also be interested in these recent articles about Converting, Mapping, and Uploading Shapefiles to a GPS from the ExpertGPS Blog