We have posted about several differing geocoding solutions for the Mac. All of these programs allow you to embed location information in the EXIF data of your photographs, thus specifying where the photo was taken as well as the time, date, etc. The newest entry into the Mac geocoding sweepstakes is HoudaGeo, which has just been released as a public beta. Like some of the others, it allows you to tag your photos either by importing tracking data from a GPS device (syncing using the time stamps) or by using an interface with Google Maps. Once the photos have been tagged you can export them to Google Earth with a single click:
HoudaGeo is a free download while it's in beta but will eventually be shareware.