1. An interoperability system for providing access to a plurality of services by a plurality of users having associated client machines, each of the plurality of users being associated with one of a plurality of independent enterprises, the plurality of services being associated with and controlled by a plurality of independent service providers and employing a plurality of interfaces at least some of which are not directly interoperable, the system comprising: at least one data store having a directory stored therein which maps an identity corresponding to each of the users to a policy framework which defines access policies relating to the services, the identity for each user identifying the associated enterprise, the at least one data store also having a plurality of rich client objects stored therein which are operable to be launched within browser environments on the client machines, and to interact with the services via the interoperability system; and at least one computing device which is operable to connect with each of the client machines and each of the interfaces associated with the services, to selectively upload the rich client objects to the client machines with reference to the directory, and to selectively facilitate interaction among the uploaded rich client objects and the services with reference to the directory and the policy framework, thereby enabling the users associated with different ones of the enterprises to independently access the plurality of services using the interoperability system.