check it out here
free ver. and a $100 ver.
http://www.maxwellrender.com/index.php/maxwell_for_google_sketchup/download_buy
Thanks Doug,
TurboFloorplan - IMSI Design also has both a free and pay for Sketch up product for rendering.
Renditioneer
http://imsidesign.com/Products/Renditioner/tabid/1756/Default.aspx (http://imsidesign.com/Products/Renditioner/tabid/1756/Default.aspx)