If you move computer and want to export your My Places, or want to save your My Places and access them elsewhere, here are some ways to do it.
Saving your My Places file to another computer
If you are still using the old computer, load Google Earth and right click on the My Places icon. Choose the Save Place As option from the pop-up menu:
Select the KMZ file (it’s smaller: a KMZ is a compressed version of a KML file and these files can get quite big):
Save it to somewhere you can find it again.
Sending your Google Earth My Places via email
Another option is to send it via email.
Select the My Places folder in the left hand pane:
Click on the email icon at the top of the main window:
And follow the instructions:
Finding and saving the file on another drive
If you’re not using the computer you want to save your My Places from, then you’ll have to find the kml file first.
The file is stored in the folder C:\Documents and Settings\<username>\Application Data\Google\GoogleEarth and is called myplaces.kml.
So you can either dig down to that folder or search for the file itself.
Once you’ve found it, save it to the place you want to keep it.
Importing the My Places file into Google Earth
This is pretty straightforward: Once you’ve opened Google Earth, just click on the File/Open menu:
and open the myplaces.kml or myplaces.kmz file.
GoogleEarth will insert the MyPlaces folder at the bottom of any existing places in the Temporary Folders in your Places pane
You’ll need to move those places you want to save at the end of the session or they’ll be deleted.