This morning at the OGC Technical Committee meeting, the Google Earth & Maps team announced an alpha of libkml, an open source (BSD) library for reading/parsing/writing KML 2.2. It’s a C++ library, but includes SWIG bindings for Java, Python, Ruby, Perl and PHP. The hope is that this piece of code will help developers build comprehensive, robust KML support into their applications. But note, this is NOT a mini-Google Earth. You just get KML support – there’s no way to get that streaming earth imagery goodness that you see in GE, although I suppose you can combine this with a map access API (from Google, Virtual Earth, Yahoo!, etc.) to get nice base maps in your app. Enjoy!