At http://www.babel3d.com you can upload 3D models to be translated into a few (selected) other formats. Online and free.
Babel3D is an online 3D file translation service. The input for translation to Babel3D can be an Autodesk 3DS, DXF, DWG, Rhino 3DM, SketchUp SKP, STEP, IGES or OBJ file. These files can be translated into the 3DS, OBJ and XAML 3D formats. Additionally, Babel3D also allows you to convert DXF and DWG files to 2D PDF format.Beware that no info is given on the precise version numbers of the formats, so it is not clear if the systems handles DWG 2010-format files (created in AutoCAD 2010 or 2011). SketchUp format is release 7, not 8.