A360 VIEWER - Free online CAD Viewer
Glovius - Extensible & customizable 3D viewer, for consumption of product design data.
eDrawings Viewer - View, print, and review all types of eDrawings files Built-in Viewer
IGES2STEP - Freeware CAD file viewer for Windows XP/2000/NT
PartXplore - The most powerful, high-speed?CAD file viewer and analyzer
Autodesk DWG TrueView - Get a free DWG viewer to view, open, edit, and convert .dwg files, the native file format for AutoCAD files. DWG Trueview includes DWG TrueConvert.