As far as I understand it is possible to store OSM Maps in “OSM-XML” format.
Google Earth and especially Marble might be able to show locally saved data if it is in KML or GPS format.
My questions:
Which other programs can handle OSM-XML Data?
Is it possible to translate OSM-XML into KML or GPX (GPSBabel does not work)?
At this time there is no finished product that will show vectors on marble/Google earth. But I’m guessing people are working on Marble support beyond just show the images.
There are converters that can convert to KML, but I don’t know how good these work atm.