The next generation wireless mobile network will be a heterogeneous networking environment consisting of various networks with heterogeneous implementations. Discovering and selecting the optimal networks for delivering an end-to-end networking service has significant impact on the service quality offered to networking applications. One of the main challenges to network discovery and selection is the heterogeneity of the coexisting networks in such networking environments. A key to solving this problem lies in flexible and effective interactions among the heterogeneous networks, the network control plane, and various user equipments. The Service-Oriented Architecture (SOA) is gaining high attention and acceptance in IT industry due to its power for coordinating heterogeneous systems for supporting various application requirements. The SOA offers a promising approach to facilitating network discovery and selection in wireless mobile networks. In this paper, we investigate applying the SOA principles in wireless networking environments and propose a service-oriented architecture for network discovery and selection. The developed architecture and technologies are network-independent; thus are applicable to various network systems in heterogeneous wireless mobile networking environments.