Service-oriented architectures don't have to cover the entire enterprise; they can be process or application focused. This recent article on business intelligence tools puts SOA in another light; as the infrastructure that supports a specific set of applications. Here, an SOA "allows different BI services to perform specialized tasks and, when necessary, to be distributed across multiple servers."
The definition of SOA here is much narrower than what Britton and I have been talking about in this blog, in which various standardized application components can be arranged and re-arranged in accordance with changing business needs across the enterprise. But it illustrates the fact that SOA will not happen overnight; but, rather, will be built out gradually in increments. View any vendor claims of being able to supply SOA in one package with a very healthy dose of skepticism.