You can download various KML files to overlay on Google Earth. You can find KML files like Volcanos.KML in the Google Earth Gallery
A KMZ file done by my friend Jim Gates by his cabin in Pennsylvania
See Attachments below
Google Lit Trips
Great article about Jerome Burg!
Google Lit Trips: Bringing Travel Tales to Life in Edutopia
An archived ISTE webinar by Jerome Burg about Google Lit Trips
Google Lit Trips vidoes in Vimeo
See Attachments (below) for the kmz file
You can see samples from the Google Lit Trips site for the book Seaman and download the KML file from this link.
Google Earth Pro
Google Earth Sightseer Newsletter
My Diigo Resources
My Diigo List (top 15) of Google Earth resources
Google Earth Lesson Plan by Chad Kafka (who is an ADE) related to Lewis & Clark
World War II images in Google Earth