Enterprise software is being transformed from an installed product to a hosted service whereby customers pay a subscription fee to access functionality using a web browser or other clients. The service-oriented architecture (SOA) and web services will play a key role in driving the vision of software as a service. As the number of services and users grow, there is a need for a trusted service broker to manage services offered by service providers and subscribed customers. In this thesis we propose a framework for a service broker for software as a service (SaaS) applications. One of the novel features of this broker is an environment for an Internet desktop that allows users to transparently access and use SaaS applications from anywhere at anytime as long as they have a computer and an Internet connection. This model has a very close resemblance to a thin client model and the old mainframe setup where the terminals really didn't need to have any special CPU power or mass storage capacity. A proof of concept implementation is discussed; it enables users to have an integrated set of applications that closely reflect their business process or the task they are trying to accomplish.