AutoDesk provides a toolbar to allow the use of ESRI .shp files and map services in AutoCAD. You can find the ArcGIS for AutoCAD toolbar at the following url: http://www.esri.com/software/arcgis/arcgis-for-autocad/download. Further instructions for installation and use of this toolbar have been provided for your convenience.
If you have ArcGIS and AutoCAD products, in ArcGIS you can convert the downloadable files to AutoCAD format(s). However, you may have to convert the files into smaller geographic sections as the files will be very large in size.