Microsoft seems to have pulled the AD integration feature for the Remote Application list from the Windows Server 2008 RC0 Terminal Server Web interface. It was present in Beta 3 but no longer available in RC0.
Windows Server 2008 supports application level remoting with seamless windows (as it is called in Citrix environments) for the first time. This allows you to provide users with just the window(s) for their applications on their desktop instead of presenting them with a full desktop for each server required. The list of available programs can be presented to the users through a web interface called TSWeb for the first time (not unlike the Citrix Web Interface has offered for some time now).
In Beta 3, the list of remote applications could be populated from a selected Terminal Server's configuration, or from software advertising Group Policies within Active Directory. The latter method provided the added effect that only those applications advertised for the particular user logging on to the TSWeb interface would be shown in the list, thereby eliminating clutter and confusion as user click on a program only to get a message that they aren't authorised to use it. This is how the interface looked in Beta 3:
In RC0 the option to populate the Web part from AD has been stripped from the configuration page, leaving only the Terminal Server option:
The reasons for seemingly pulling this feature aren't clear to me, but could be related to incomplete testing or functioning of the involved components. I sincerely hope it resurfaces in the RTM version, as this feature (user/group/OU based application availability) has long been available for Citrix environments.