This may have been out for as much as two weeks, but I haven’t read about it anywhere. If you are a Google Earth developer, Google has released a KML 2.1 Tutorial. This is part of the June 12th announcements where they released Google Earth 4 Beta which supports the new features in KML 2.1. Just a sample of the new features are: Texture maps in 3D models, level of detail regions (so you can control detail on aerial photos (or other information) as the user zooms in/out), more efficient network links, radio button folders (allow multiple views of the same scene), and more. If you are a developer, this tutorial might give you more insight on the things you can do. Brian Flood also recently wrote a summary of some of the new KML 2.1 features.