Autodesk has recently released a new, free, utility that will help you convert as well as view drawing files.

DWG TrueView is a viewer for drawing files. You can pan, zoom, plot, turn layers on and off, and publish DWF files all from this free viewer.  This version of DWG TrueView now incorporates the functionality of DWG TrueConvert.  This allows you to convert DWG files to and from any version of AutoCAD back through AutoCAD 14. One of the improvements to this converter over the old batch drawing converter that has been available for some time, is that the DWG TrueView program does not require that a certain version of AutoCAD is installed on your computer. So if you have not upgraded yet and are getting files in a newer format than you can use this will be a big help.