To make the most of iPhotoToGoogleEarth you'll need to have GPS infomation stored in the Exif tags. If you don't know what that means this plugin probably isn't for you. GPSPhotoLinker is recommended for GPS tagging.
Once you have photos tagged correctly, select your images and then Export.
PhotoToGoogleEarth is donation-ware. If you appreciate what I have created please send me a dollar or two via PayPal, or a postcard. After tens of thousands of downloads I can still count the donations without taking my shoes off :/