Are you asking if you will still be able to use AutoCAD2006 (as a program) or the files produced in AutoCAD 2006? Chances are installing AutoCAD 2009 will take everything that pointed to 2006 and turn it into a pointer to the new updated program, 2009. But, 2009 should be backwards compatible so you should be able to edit and change the files created in the 2006 version.
Hope this helps!
Last Wiki Answer Submitted: January 18, 2009 5:50 pm by Schmidtw11,205 pts.