Configuring Terminal Services Licensing
Windows Server 2008 requires that at least one Windows Terminal Services license server be installed and running on any network that uses Application Server mode. If a license server is not installed within 120 days, all Windows Terminal Services connections will be disabled. Windows Terminal Services requires a separate Terminal Server CAL for each user or device in addition to any Windows Server CALs you might need. The Terminal Server Licensing server does not track per-user license usage, but it does enable you to install per-user licenses.
Installing Terminal Server Licensing
In SBS, installing the Terminal Server Licensing service on the same server that is running Terminal Services is a reasonable choice, ...