So yesterday was announced and also made available the AutoCAD WS capability (aka Project Butterfly)
Very cool stuff where you can share online your drawing with others in a collaborative session where you can chat and decide on changes virtually.
There is the capability here to be sharing your design with others in the team which may not be in your office and marking up the changes required for example.
Civil 3D dwg's open in the product in their wireframe mode from what I have tried with no problems.
So give it a go.
Civil 3D drawing in AutoCAD WS
Here is the original in Civil 3D
Jack Strongitharm