I recently came across details of a nifty tool on the Arc Scripts site that should be of interest to AutoCAD Map users (thanks to
http://giscadblog.blogspot.com for the tip). The tool titled "AutoCAD World File Adjustment And Projection Files" uses AutoCAD to modify CAD drawings from information in an ESRI World file. This tool will also assist you in creating companion ESRI Projection files for your AutoCAD file. See more at http://arcscripts.esri.com/details.asp?dbid=14448 - thanks again to Don for pointing this one out!