The Intelligent Network (IN) architecture promises easy development and fast deployment of sophisticated communication services. However, the centralization of service logic programs used to provide IN call processing and other house-keeping functions performed at the Service Control Point (SCP) may create bottleneck problems. In this work, we develop queuing models for the SCP and introduce a two level congestion control mechanism to provide better quality of service guarantees to IN services. The evaluation of the system is done via simulation.