The chapter “Ubiquitous Services and Business Processes” discussed the benefits for real time enterprises of service oriented architectures (SOA) in terms of reusability and flexibility. Web services are one incarnation of SOA. This chapter gives a brief introduction to SOA. It discusses the attributes that define SOA, the roles of the participants in a service oriented environment. The essence of SOA is that clients use services offered by a service provider to get a task done. For the moment we simplify service to “a software component with network connection”. Services are offered with a description at wellknown “places” (also called registries, repositories), where clients choose services according to their needs. The chapter discusses several approaches to describe services and to look for them. Moreover, some well-known systems, and also current research, are discussed.