I have a bunch of locations stored in "My Maps". Is it possible that I create a KMZ file that I can use in Google Earth?
Click on the button for "link" above the map. Paste that link into the browser and hit enter. Then, add
&output=kml to the end of the URL, and hit enter. You will be prompted to download a KML file, which will contain all of the points in the map.
Seeing that there's no convinient way of doing this provided by Google, I've created a tiny online app for export of your starred locations to KML: http://gexport.somee.com/ It's very primitive, but it does the job.