Alibre has created an add-on to their Alibre 3D Publisher tool. It will take a CAD drawing and convert it into the Google Sketchup format. There are 14 examples already in Google's 3D warehouse.

Press Release:
http://www.marketwire.com/mw/release_html_b1?release_id=240200

Product Demo
http://www.alibre.com/promos/online/3DSketchUp.asp?SOURCE=PRggl2007

Google 3D Warehouse:
http://sketchup.google.com/3dwarehouse/cldetails?mid=fbb15f94722844eb15064c407acafb2c