Is this REALLY worth it … 10% off! … <http://windowsvistablog.com/blogs/windowsvista/archive/2007/03/20/purchasing-additional-windows-vista-licenses.aspx>
For customers who acquired a full or upgrade version of Windows Vista from retail or pre-installed, we’ve got a pretty sweet deal. We’re announcing the Windows Vista Additional License program, which provides the ability to install the same edition of Windows Vista on any other additional computers you may own. The program allows customers to purchase up to 5 additional licenses for PCs they own at 10% off the suggested retail price.
BUT I have also found the “Windows Vista Family Discount” that offers over 60% off* household PC upgrades to Windows Vista Home Premium