The Virtual Computing Environment (VCE) should "on demand" collect and aggregate distributed resources, and provide efficient publication, discovery and subscription mechanisms. Since resources are usually virtualized as services, the goals of the VCE largely rely on service oriented computing technologies. However, Service Oriented Architecture (SOA) organizes services in a "provider-centric" manner, which brings a critical problem: More services come to being, more complex and difficult the service discovery and subscription become. A "consumer-centric" approach is proposed to addressing this problem. First, function similar services according to consumer’s functionality requirements are dynamically aggregated as a service pool. The pool will act as a virtual service so that consumers only discover and subscribe the service pool instead of a large number of candidate services. The qualities of the services in a service pool could form a spectrum of QoS so that consumer’s quality requirements can be satisfied by automated QoS negotiation. Based on the service pool, the VCE could provide an "on demand of consumers" way for resource sharing.