Ubiquitous environments are characterized by devices that share information with one another. Such environments can be created dynamically by creating association between devices at runtime. This association requires selection of services on these devices, a technique known as service composition. The existing service composition approaches are mostly restricted to service matching and consider functional aspects of the association only. We propose a QoS-aware device selection in the ubiquitous environment, but also integrating user-preferences with QoS by taking into account network heterogeneity (variety of access technologies). We search for the nearly optimal solution among a number of candidate solutions of service composition that maximizes QoS parameters and user-preferences specified by user keeping in view network heterogeneity