Bing Maps has added OpenStreetMap to its list of layers. See here for a post from Chris Pendleton (at MS)about it. It doesn’t sound that straight-forward to add the layer and not quite sure of the point to this. It might provide a more stable platform to view OSM but surely the road data from Bing Maps (Navteq) and Google Maps (TeleAtlas) is enough for the casual user. So will OSM break into the main stream? There is an interesting article by Steven Feldman in this month’s GIS Professional about OSM and the next steps (brief outline here).