Hello Nikola!
Just out of curiosity: I've just had a glimpse at 'Tagmap' and also 'KML content type' (http://drupal.org/project/ct_gearth). After a while something struck me and that's why I am asking: What about the contribu module 'Open Layers' (http://drupal.org/project/openlayers)? Wouldn't it make sense to use it as a foundation for your efforts & projects?