The need to change software easily to meet evolving business requirements is urgent, and a radical shift is required in the development of software, with a more demand-centric view leading to software which will be delivered as a service, within the framework of an open marketplace. We describe a service architecture and its rationale, in which components may be bound instantly, just at the time they are needed and then the binding may be disengaged. This allows highly flexible software services to be evolved in inInternet timele. The paper focuses on early results: some of the aims have been demonstrated and amplified through two experimental implementations, enabling us to assess the strengths and weakness of the approach. It is concluded that some of the key underpinning concepts - discovery and late binding - are viable and demonstrate the basic feasibility of the architecture.