Systems and methods are described for exposing the third party call control functionality of a telecom signaling network as a web services interface. An intelligent network application part (INAP) plug-in is used to provide the translation logic of simple web service interface calls received from a client application, into the lower-level signaling protocol invocations needed to provide the third party call functionality at the network level. The INAP plug-in is deployed in a service access gateway positioned between the telecommunications signaling-based network and a multitude of service provider applications that seek to access various functions in the network. By implementing the INAP plug-in, applications are provided with access to third party call control (3PCC) within the network, without the necessity of invoking low-level signaling needed to establish calls, terminate or cancel calls, as well as obtain various call information.