The Google Earth Extension for AutoCAD is a very usefull tool. It allows you to import a Google Earth image into AutoCAD, publish your 3D model to Google Earth, drape a Google Earth image onto a 3D mesh in AutoCAD, and attach time span information to your model.
The user guide provides easy to follow steps for importing a Google Earth image into AutoCAD, publishing 3D model to Google Earth.
For those who have upgraded to the Autocad 2010 family, you can download bellow the updated utility .
The Google Earth Extension download contains installers for AutoCAD 2007, 2008, 2009, and 2010 in one zip file. Download, unzip, and execute the installer that matches your version of AutoCAD.