1. A method for providing surveillance of messaging service messages in a communications network, the method comprising: in a signal transfer point (STP): receiving a signaling message at the STP; determining that the signaling message requires processing by the STP; evaluating a messaging service surveillance (MSS) processing discrimination parameter in the signaling message; examining the signaling message to determine message type based on said parameter; determining based on said message type that the message is a messaging service message and if so, determining whether the message is destined for a Short Message Service Center (SMSC); identifying, using a subscriber surveillance database within the STP, the messaging service message as being associated with a subscriber that has been placed under surveillance; generating, using a surveillance function located within the STP, a copy of the messaging service message; and forwarding the message copy to a surveillance entity.