Just wanted to make you aware of one post that explains to some of you who wondered about Google Earth in Civil 3D 2013. Here is a forum post with an official statement from Autodesk posted by Dave Simeone, Senior Product Manager for Civil 3D.
Due to limitations on the use of the Google Earth API, AutoCAD® Civil 3D® 2013 does not include API access to allow customers to import Google Earth imagery and/or surfaces directly into Civil 3D. We are aware of the importance of including preliminary surface and aerial imagery in your design workflows and are actively looking for an alternative. However, we cannot share any specific information about potential future product enhancements. When appropriate, we will communicate technology plans via various channels including Autodesk Labs, Facebook, Blogs and the Civil 3D Discussion Group.