1. A method of managing an interface, the method comprising: providing, in an Identity System configured to provide identity management services for users on a network, an application program interface registration list comprising a plurality of entries, each of the entries correlating an application program interface to a program outside the Identity System, wherein the Identity System supports a plurality of application program interfaces; identifying, in the Identity System, an application program interface corresponding to a program, based at least in part on an entry in the application program interface registration list; and invoking said program outside said Identity System in accordance with said identified application program interface.