Converters between DWG, PDF DXF, DWF, and several image file formats, and AutoDWG Attribute Extractor to retreive block information, all as standalone programs. http://www.autodwg.com/
SolidConverter DWG converts dwg and dxf files to other versions. Utility run as a standalone utility, batch command line processing or plug-in for AutoCAD 2004. http://www.soliddocuments.com/