I'm afraid that AutoCAD 2006 doesn't seem to be available any longer (but you can purchase 2011 as a download on the AutoCAD site). You may be able to find a copy on eBay. Is there any particular reason why you need the older version?

A web page related to acesulfame-k and sunette hazards. AutoCAD 2006 is simple, less complexive, user enhanced interface, easy to use, rich feature software that supports both 32-bit and 64-bit operating system environments. AutoCAD 2006 has compatibility support for windows XP, windows vista, windows 7, windows server 2008 and windows 8 as well.

I'm assuming, of course, that you were talking about buying the software rather than enquiring where you could download a pirated copy (that would be liable to get you banned from the forum, so I'm sure that wasn't your intent). The company's web site is always the best place to look initially. Download Official Video Separuh Aku.