A telecommunications network uses a supervisory service broker in a packet messaging environment, particularly Session Initiation Protocol (SIP) messaging, to changeably allocate and to account for the usage of network resources by users. The SIP INVITE and other messages are passed through the supervisory broker, monitored for accounting and potentially redirected to change allocations of resources. The resources can generally comprise applications and applications servers such as media storage and playback, voicemail and directory services, subnet messaging and instant messaging, voice-over-Internet, wireless linkages and others, and can be logically grouped in packages that are allocable. Users such as telecom carriers and others can contract for usage and also can contract to provide resources for use by others, in an unlimited way or according to terms, and for appropriate credit.