Create a kml tag reader for ListStyle (including a GeoDataListStyle backend class and the needed tag handers for the inner tags) Hint: The existing tag handlers and geodata classes are good examples. See also our notes on KML support in Marble:  http://marble.kde.org/kml-guide.php

Instructions to install Marble can be found in http://marble.kde.org/sources.php (checkout the development branch)

It's a good idea to join the #marble IRC channel in freenode for help and discussion.