Google have
announced the release of
libkml 0.1, a C++ library for reading, writing and manipulating
KML. KML is a file format used for displaying GIS data in a mapping browser such as
Google Maps.
If you're not a C++ programmer, the libkml build system can produce swig bindings for perl, PHP, python, Java and Ruby.
libkml has been released under a BSD licence. There is also a brief
starter guide for the library.