AutoCAD Map 3D 2010 has a new FDO provider that allows you to publish drawings into Google Earth. But there are times when you need a georeferenced image inside AutoCAD Map 3D to use as an underlay. The Google Earth Extension for Map 3D is a handy application to get this done.
Here is the URL to download and install the Extension:
http://labs.autodesk.com/utilities/google_earth_extension_beta/