Starting today we are removing the distinction between Amazon EC2 running Windows and Amazon EC2 running Windows with Authentication Services. With this change, Windows instances have been upgraded to enable the use of Authentication Services, like LDAP and Kerberos, at no additional charge. Additionally, if you are running any Windows with Authentication Services instances you will now be charged the same price as Windows instances, a savings of 50% on the hourly rate.
We will remove the current Windows with Authentication Services AMIs starting on October 15th. If you need a version of this AMI, please re-bundle your own copy by following instructions that can be found in our Getting Started Guide.